Image file formats

Image file formats


There was a time almost 30 years back where getting a photograph clicked was a significant affair in the family and was usually done for only official documents. The technology has advanced so much now that taking photographs has become much easier than drinking water from a bottle. We unknowingly deal with a crazy number of images daily whether it is by taking photographs, sharing them, downloading them, uploading them and the list goes on and on. But generally, we don’t even care how these images are made, how for each purpose there is a different file format and how much more practicality these individual file formats provide.

I too until recently didn’t care about them, but one day my roommate (who BTW is an avid photographer) was editing a photograph he clicked and I in my usual sneaky self just couldn’t let him do anything without disturbing him. While doing this I saw that the photograph he clicked had much more detail than the ones I clicked with my phone. At first, I thought it must be because of his DSLR but he told me then he clicked it with my phone. I asked him how he magically improved my phone camera and he said that he clicked and saved the photograph in RAW format. Intrigued, I then have just been reading up and getting myself familiar with all the different file formats and for which purpose each is used. If you too are curious, continue reading!



Before we dive into some deep stuff about image file formats let’s first get an idea about the basic stuff related to this field that’ll help us understand the technical stuff more easily.

 RGB refers to combining red, green, and blue light creates different colors, which is the standard method of producing color images on screens, such as TVs, computer monitors, and smartphone screens.

CMYK stands for “Cyan Magenta Yellow Black.” These are the four basic colors used for printing color images. Unlike RGB (red, green, blue), which is used for creating images on your computer screen, CMYK colors are “subtractive.” This means the colors get darker as you blend them.

A lossy algorithm removes some information in the digital file to reduce the file size. However, the loss of information lowers the overall quality of the image.

On the other hand, we have a lossless algorithm, which retains all the information in the image. The original image data is maintained regardless of how often you might copy, re-save, or compress the original file. But that also means lossless files take a lot of space in your storage device.

Difference between a lossless and lossy image

Some image files (Vector files, in general) support transparency, specifically transparent backgrounds. This is super useful when you want to put your logo on a background color other than pure white. Transparency is shown with gray and white checks.

A pixel is a square of color in a raster image. Images are defined by the number of pixels per square inch.

You might have also heard about raster and vector images thrown around in the photography community. However, what is the difference between them?

Source – VectorStock

Raster images are made of a series of pixels, or individual blocks, to form an image. JPEG/JPG, GIF, PNG, and BMP are all raster image extensions. Pixels have a defined proportion based on their resolution (high or low), and when the pixels are stretched to fill space they were not originally intended to fit, they become distorted, resulting in blurry images. To retain pixel quality, you cannot resize raster images without compromising their resolution.

Raster Image Format

Vector images are far more flexible. They are formed using proportional formulas rather than pixels, i.e., they contain vector lines, fills, and patterns that can be dynamically stretched without losing resolution and are not limited to pixels. EPS, AI and PDF are perfect for creating graphics that require frequent resizing. Logos and brand graphics are usually created as a vector file. Although the real place where vectors shine is in their ability to be sized, however, we want without losing any of their quality.

There is a lot of mix-up about DPI and PPI too on people’s minds!

DPI refers to “dots per inch” the print puts on the paper and PPI translates to “pixels per inch.” Images with a low PPI are lower quality than images with a higher PPI. These units of measure are essential for determining if the density of pixels in an image is appropriate for the application you are using.

The biggest thing to note when determining what DPI or PPI you require is if you are using an image for print or web. Websites display images at 72ppi, which is low resolution (low PPI); however, images at this resolution look crisp on the web and is also used in smartphone and tablet displays. This is not the case for print. Best for printing an image will be no less than 300ppi, which is high resolution.

Vector vs Raster

Types of Image Files

1. JPEG (or JPG) – Joint Photographic Experts Group

            JPEGs might be the most common file type you run across. Its lossy compression algorithm removes details that your eye is least likely to notice to save space. A drawback of JPEG files is that unlike PNG files, the layers of a JPEG file are flattened, i.e. you can’t very much work on any previous edits. Worse, if you edit the same file several times, the edited image may become worse than the original.

JPEG files are usually used for photographs or projects on the web, in Microsoft Office documents.

JPEG files are bad for line drawings or logos or graphics, as the compression makes them look “Hazy” (jagged lines instead of straight ones).

2. PNG – Portable Network Graphics

            PNGs are amazing for interactive documents such as web pages but are not suitable for print. While PNGs are “lossless,” meaning you can edit them and not lose quality, they are still low resolution. One of the best features of PNG is that it has transparency options. This feature also allows for more efficient image editing. Photo editors and graphic designers can easily apply their edits in layers.

It’s used almost exclusively for web images, never for print images. For photographs, PNG is not as good as JPEG, because it creates a larger file. But for images with some text or line art, it’s better, because the images look less “Hazy”.

3. GIF – Graphics Interchange Format

            You must’ve seen moving images (not videos) on the web? Most of these files use the GIF format. It is great for graphics and visuals with animation. It uses lossless compression. Extreme data compression considerably decreases the size of GIF files, allowing them to load quickly on the web. The biggest downside of GIF files is that the data compression makes it extremely lossy, thus it is not recommended for photography and printing. GIF also are only limited to 256 colors, this means the image will look coarse when used for complex images.

4.  TIFF – Tagged Image File

            A TIF is a large raster file that doesn’t lose quality. This file type is known for using “lossless compression”. The information in this format is retained in layers. TIFF is the most common file type used in photo software (such as Photoshop, Lightroom, Illustrator, Google Nik, and more), as well as page layout software (such as Quark and InDesign), again because a TIFF contains a lot of image data.

We should avoid using this file type on the web – “it can take forever to load!”. TIFF files are commonly used when saving photographs for print. It’s popular among graphic artists, photographers, and publishers.

5. PSD – Photoshop Document

            PSDs are files that are created and saved in Adobe Photoshop, the most popular graphics editing software ever. This type of file contains “layers” that make modifying the image much easier to handle. The biggest disadvantage of PSDs is that Photoshop works with raster images as opposed to vector images.

PSDs are used when it’s time to retouch photos, edit artwork for digital or print or the web. Don’t use PSD if you want to post a photo online because the web is JPEG friendly or if you are ready to print your photos as many printers don’t accept the PSD format.

6. PDF – Portable Document Format

            PDFs were invented by Adobe to capture and review rich information from any application, on any computer, with anyone, anywhere. And they seem to be pretty much on the mark till now seeing how often everybody uses this format. If a designer saves your vector logo in PDF format, you can view it without any design editing software (if you have the free Acrobat Reader software). This is by far the best universal tool for sharing graphics.

They can be used for print as many printers prefer PDF or when you must display your document on the web. PDFs will keep your entire design in one package, making it easy to view, download or print. Don’t use PDF when you want to edit its contents, use other third-party software.

7. EPS – Encapsulated Postscript

            EPS is a file in vector format that has been designed to produce high-resolution graphics for print. The EPS extension is more of a universal file type (much like the PDF) that can be used to open vector-based artwork in any design editor. This makes for easier file transfers to designers that don’t use Adobe products but maybe using Corel Draw or Quark.

EPS should be used when we need to send a vector logo to a client. We don’t use EPS when we have to use photos (although they can handle raster images but are made for vector files) or when we need to display an image online.

8. AI – Adobe Illustrator Document

            AI, until now, is the image format most popular among designers. Adobe Illustrator is the industry standard for creating artwork from scratch and therefore more than likely the program in which your logo was originally rendered. Illustrator produces vector artwork, the easiest type of file to manipulate.

We use AI when we need to edit a vector design or create a logo or an icon. Don’t use it when you need to edit raster images.

9. BMP (Windows Bitmap)

            Another lossless file format, BMP was invented by Microsoft, initially for use on the Windows platform but is now recognized by programs on Macs as well. BMPs are large file sizes as color data is saved in each pixel in the image without any compression.

As a result, this provides a high-quality digital file, which is great for use in print, but not ideal for web usage.

10. RAW – Raw Image Formats

            We will be talking about the RAW image file further down the article in detail for all the photography enthusiasts or just for the geeks! But for now, you just need to know that a RAW image is the least-processed image type on this list – it’s often the first format a picture inherits when it’s created. RAW images are valuable because they capture every element of a photo without processing and losing small visual details. Due to this fewer images can be saved in your memory card or hard drive due to the massive amount of data in the RAW file.

You should use RAW image file formats whenever you are shooting and editing photos. However, don’t use them when you are working with web graphics or when you are ready to print your photos, simply because most printers don’t accept this file format.

11. DNG (Digital Negative)

            DNG is a lossless format like RAW. However, unlike RAW that uses specific formats based on camera types or manufacturers, DNG stores image data in a compatible, generic format. Thus, any software that can read or convert DNG format can be used. Converting RAW files to DNG is highly recommended as this will significantly decrease the size of the images, making them easy to download, upload, or send via email.

DNG are appropriate for use among photographers and editing but not for the web.

12. SVG (Scalable Vector Graphics)

            SVG uses an XML-based text format to describe how the image should appear. Since the text is used to describe the graphic, an SVG file can be scaled to different sizes without losing quality, i.e., the format is resolution-independent. If you were to open one in a text editor, you would see only text. This is how SVG viewers show the picture, by reading the text and understanding how it should be displayed.  Therefore, website and print graphics are often built in the SVG format, so they can be resized to fit different designs in the future.

Benefits and Drawbacks of some Image File Formats

Image File FormatProsCons
1. JPEG/JPGSmall file sizes mean more can be stored on a memory cardQuicker file transfer times, due to smaller file sizeLoss of quality due to image compression Less opportunity for image manipulation in photo editing software
2. TIFFAbility to manipulate photos extensively in photo editing softwareOption to print at the highest quality and much larger sizesMuch bigger file sizes (more storage needed)Longer transfer and loading times due to file size
3. RAWThe best quality image file is capturedExtensive options in post-processing and image manipulationThe time needed to convert and edit photos (you must edit raw files)Bigger file sizes mean more storage needed and longer post-processing times
4. DNGAbility to use image processing software such as Lightroom and PhotoshopPossibly safer option long term, to guard against the inability to open or access files in future  Extra time needed to convert camera raw files to DNG (if your camera does not have the option to supply files in this format)
5. PNGLossless compression means good image quality, which isn’t compromised when editingThe ability to maintain transparency, which is ideal for things like overlays or logosQuality will not be good enough for printing at any size
6. GIFSmall file sizes make this ideal for use on the webFiles can contain animationLimited colors mean it is not the best choice for photosDoes not support transparency
7. BMPCan be used for printing as images are saved in a high-quality formatLarge file sizes mean high storage is required
8. PSDAbility to manipulate the image extensively on separate layersOnce the image is ready it can be re-saved as any other file formatLayered files can be incredibly large due all of the additional data stored

Which is better for Photography and Image sharing?

Seeing how computer graphics have advanced in these short years numerous graphics and image editors along with file formats have come into the market and gone. Some are suited for sending e-mail while some for image editing. The best formats for sending e-mail photo attachments are JPG and PNG. These are also the most common formats, widely used on the web. Among the worst formats for sending an e-mail, photo attachments are TIFF and BMP as the file size is huge. In addition to these, graphics file formats, such as the PSD format used by Adobe Photoshop, are inappropriate to send unless the recipient asks for such file formats and has the software to open and edit those images.

PNG is a better choice for photographs while saving space. The GIF image format is also small but has a limited resolution for photographs. TIFF images are used primarily in editing applications. Although you can e-mail them, unless asked, you’re just wasting time and your bandwidth.

Generally, JPEGs should be used:  When the photos are for personal use, for social media, and small prints and not intended for large size prints, when you don’t intend to edit the photos much in post-production, for sharing images via email (without the intention of large size prints).



Details on the RAW file format


There is a lot of information about RAW image file format out there on the internet and honestly, if I was to start telling you about it this article would bore you to death.

A RAW image file contains minimally processed data from the image sensor of either a digital camera, a motion picture film scanner, or any other image scanner. Raw files are named so because they are not yet processed and therefore are not ready to be printed or edited with a graphics editor. Normally, the image is processed by a raw converter in a wide-gamut internal color space where precise adjustments can be made before conversion to a “positive” file format such as TIFF or JPEG for storage, printing, or further manipulation. This often encodes the image in a device-dependent color space. There are dozens, if not hundreds, of raw formats in use by different models of digital equipment (like cameras or film scanners). Some of them are mentioned below in a table.

RAW file ExtensionFile TypeRAW file ExtensionFile Type
.3FRHasselblad 3F RAW Image.KDCKodak Photo-Enhancer File
.ARWSony Digital Camera Image.MFWMamiya Camera Raw File
.BAYCasio RAW Image.MOSLeaf Camera RAW File
.CR2Canon Raw Image File.MRWMinolta Raw Image File
.CR3Canon Raw 3 Image File.NEFNikon Electronic Format RAW Image
.CRWCanon Raw CIFF Image File.NRWNikon Raw Image File
.CS1CaptureShop 1-shot Raw Image.ORFOlympus RAW File
.CXIFMAT RAW Image.PEFPentax Electronic File
.DCRKodak RAW Image File.RAFFuji RAW Image File
.DNGDigital Negative Image File.RAWRaw Image Data File
.EIPEnhanced Image Package File.RW2Panasonic RAW Image
.ERFEpson RAW File.RWLLeica RAW Image
.FFFHasselblad RAW Image.RWZRawzor Compressed Image
.IIQPhase One RAW Image.SR2Sony RAW Image
.J6IRicoh Camera Image File.SRFSony RAW Image
.K25Kodak K25 Image.SRWSamsung RAW Image
.X3FSIGMA X3F Camera RAW File  

Let’s look into in detail about the benefits of shooting in RAW:

  1. We get the highest quality possible. All cameras technically shoot in RAW, the difference is that some automatically do their processing and convert the RAW file into jpeg according to the settings applied. When we shoot in RAW we can do our processing on our computers and produce better results.
  2. We can record greater levels of brightness, which are the number of steps from black to white in an image. The more you have, the smoother the transitions of tones. These steps provide you to make further adjustments in an image without losing significant quality.
  3. When you make changes in a RAW file, you’re not doing anything to the original data. What you’re doing is creating a set of instructions for how the JPEG or TIFF (another file format) version should be saved. The magnificent part of this is that you never have to worry about ruining an image, you can easily go back and start over again.
  4. Because of the finer gradation of tones and colors, you’ll get better prints from RAW files.

Every pro has its cons let’s talk about that now:

  1. It takes more time to shoot in RAW than in JPEG
  2. RAW images are 2-3 times larger than any other file format so they take up a lot of space. And for a professional photographer who takes thousands of photographs, this can be quite expensive.
  3. Since RAW files are larger and contain more information, it slows down the camera and you can’t shoot in succession.

However, all three cons are getting overshadowed by its pros. Since storage space is getting cheaper, editing software, cameras, and equipment are getting better and faster RAW is still a very popular choice among the professionals.

Different Editing Software supporting Different Formats


Now that you’ve learned about so many image file formats and graphics, photo editors. We have only talked about only powerful image editors in this article but what about image organizers and sharing apps. There are thousands of photographs we are dealing with on our phone and laptops, it is a very cumbersome job finding a single photograph from our collection. The job is akin to finding a needle in a haystack! There are several such software out there which may be available on the internet but whether they are any good that’s another question. Recently, I discovered a software which if not surpasses certainly gives its competitors a run for their money. “Jmedia App” is the name of the software, which is relatively new in the market but not lacking in any aspect when it comes to its usability and features. This app is a powerful image, video and document organizing, sharing and backup app. This suite comes with Mac, iPhone, and Android apps with Cloud integration. This helps users to quickly find, tag and share media with friends & family. JMedia allows you to transfer videos, photos, and documents from one device to another. Its features include accessing and organizing your multiple Terabytes of Images, Videos and documents with complete ease, it is 200 times faster than Bluetooth technology with transfer rate up to 20 MB/sec, transfer supports original quality of photos, videos and documents and much more. Do give it a try.

This Post Has One Comment

  1. Alex

    Very detailed article. Good one!

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