Understanding Common Image File Types

Understanding Common Image File Types

13min read  

20 May 2021

When working with images, it’s easy to get fully immersed in the creative process and neglect the technical aspect of it all. Which image format you store your graphics in might seem insignificant until you try to open your file on another device and realize that it’s completely distorted or incompatible with that operating system.

Here’s where image file types jump in to ensure image data is saved properly and your files are ready for the next step — whether it be printing, transferring, sharing on the web, or storing for future use.

In this blog post, you’ll find 11 of the most common image file types and will learn when and how to use them. But before we get there, let’s swiftly go over some technical terms to make sure you don’t get tangled in the field terminology.

 

Raster vs. Vector File Formats

When it comes to image file format jargon, “raster” and “vector” take the crown. As a newbie, it’ll be hard to wrap your head around all the different file types unless you’re familiar with these two terms. So here’s their breakdown.

Image files are categorized into two groups: raster and vector images. A raster image is composed of individual pixels — i.e., colored blocks that form a grid. Raster images have set resolutions, and when enlarged, can appear blurry as the pixels comprising them get stretched. 

This is why when you upscale a raster image, you see individual pixels, and the overall image loses its sharpness. Most graphics you come across on the web — be it blogs, social media, emails, etc. —  are raster files.

sharp vs pixelated raster image

Vector graphics, on the other hand, are curve-based and resolution-independent, allowing more flexibility when resizing. Software programs read vector illustrations as mathematical equations where changing a variable doesn’t change the entire equation. 

As a result of being constructed with points and lines rather than pixels, vector images are freely scalable and retain image quality regardless of proportion. Logos, icons, print designs, artwork, or other graphics that need frequent scaling should be stored as vector files. It’s the easiest way to ensure designs look identical, whether displayed on small business cards or large banners.

vector vs raster files when enlarged

Source: City Planner

As you can see in the image above, vector illustrations can be zoomed in indefinitely without distortion in form or color. The computer sees vector graphics as an aggregate of various shapes and is thus able to preserve their outlines at any size.

 

Image File Compression

Another step to deciphering the image format lingo is to understand lossy vs. lossless compression. Image compression is the reduction of image file size achieved by compressing data. Some compression algorithms, for instance, merge similar pixels in a raster image file, reproducing the same graphic with slight information loss that’s usually imperceptible to the naked eye.

There are two types of image compression methods: lossless and lossy. Lossless algorithms minimize file size without altering the uncompressed image — there’s no data loss, hence the name “loss-less.” The final image file size will be larger compared to lossy files, but the quality of the photo will remain untouched. The ZIP file format is an example of lossless compression.

Lossy compression compromises image quality for a smaller file size by recreating the original graphic with inexact approximations. The extent of compression will determine how sharp or blurry the compressed image ends up looking. Low-compression files will have more definition than high-compression files.

original image vs low compression vs high compression

Lossy files are more convenient to store, share, and download due to the small file size. That’s why they’re so dominant online. But in cases when image quality matters more than the time it takes to load that image, lossless compression is preferred.

 

Raster File Formats

Now that we covered the basic terminology of image files, we’re ready to dive into the most commonly used image file formats. We’ll begin with raster file types and explore the distinguishing features and use cases of each.

 

JPEG (Joint Photographic Experts Group)

JPEG, alternatively called JPG, is the most widespread format for web and social media images. Graphics in this format are lossy and thus small in size and low in quality. Thanks to its high compatibility with browsers and operating systems, this image file type is globally accepted. 

JPEGs with high resolution and low compression work great for prints. Keep in mind, though, that low-resolution JPEG files will look blurred when printed. In addition to that, screenshots or graphics with a lot of text will likely look smudged in this format because of the lossy compression.

JPEG requires a solid background for images and does not support transparency or layers. This makes this format unfit for extensive editing as all changes are saved on one layer.

JPEG image file type

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JPG vs. JPEG

Alright, let’s clear one thing up: JPG and JPEG refer to the same image format, and it makes no difference which file extension you use. The reason why both options exist is that Windows initially had a three-character limit for file extensions, so JPEG was reduced to JPG to fit the requirement. The restriction no longer stands, but both names are still in use today.

 

PNG (Portable Network Graphics)

As opposed to JPEG files, PNGs are lossless, but they don’t provide the highest resolution. While they may not work for print, PNG files are perfect for the web. They look sharp and clear online and support transparent backgrounds.

PNG has universal software compatibility and is easy to share, store, and save. Thanks to its lossless compression, this file format is better suited for editing compared to JPEG. Another area PNG shines in is color support, incorporating 8-bit, 24-bit, and 48-bit images.

With their high color depth, PNGs look vibrant on the screen and handle text better than JPEGs. As PNG allows a transparent background, you’ll often come across logo files in this format. But do keep in mind that as a raster file, PNG is not scalable.

PNG image file type

 

GIF (Graphics Interchange Format)

GIFs are animated lossless graphics operating within an 8-bit palette range, which does not give them a lot of color depth but is sufficient for most web illustrations and diagrams. The format is widely used on social media platforms, especially ones that are graphic-reliant like Tumblr and Pinterest. 

Limited color support is what allows GIFs to preserve minimal file sizes, provided that image quality will be compromised in exchange. You get a transparent background with this file format, but there’s no layer support, so expect limited editing capacity. 

Regardless of how you pronounce GIF (Is it “jiff” or “giff?”), you can use this graphic type for simple animations, social media images, quick logo reveals, banner ads, and more. But when it gets to print or photography projects, GIF won’t be able to give you the high resolution you need.

GIF image file type

 

TIFF (Tagged Image File Format)

TIFF (also called TIF) files are flexible and sustain high image quality even after compression, copying, or other manipulation. As you’ve probably already guessed, HD images are synonymous with heavier files, which rules TIFF out as an optimal image format for the web. Having TIFF images on your website will noticeably slow the latter’s performance down, so be careful with this file format.

While TIFF is not widely accepted by browsers, it’s highly regarded in print as a photography file standard. You’ll find this image format in most advanced graphic design programs. TIFF images can be lossy, but they’re mostly used in their lossless form.

TIFF image file type

 

WebP (Web Picture)

WebP is a web-oriented image format developed by Google to secure faster page load time. The format was later modified to support animation as well. WebP graphics can be lossy or lossless and remain small yet crisp in both forms when used online. 

WebP supports an alpha channel (i.e., image transparency) and metadata, helping graphics rank in Google Image Search. It’s easy to convert other web image file types like JPEG or PNG to WebP. The latter sets itself apart from competitors by providing identical image quality yet reducing file sizes by up to 34%.

This format is compatible with common browsers and software libraries.

WebP image file type

 

PSD (Photoshop Document)

PSD files are Adobe Photoshop documents that have become a standard for graphic designers and professional photographers alike. This versatile image file format is prepared to handle pixel-level, multi-layered editing and can be converted to most of the major file types within Photoshop itself.

Photoshop documents are the best choice for storing projects that need thorough retouching, such as photographs, digital artwork, product mockups, etc. Since they support multiple layers, filters, effects, and even animation, PSD files can contain a huge amount of data and quickly grow in size as a result. If you intend to share your projects online, it’s best to convert PSD to web-friendly formats first.

PSD image file type

 

RAW (Raw Image Formats)

If you’ve ever taken a photo with a camera, you’ve probably noticed that it’s automatically stored in a RAW format. Once you transfer and edit the file using a software program, it trades its format for another one.

The name of the file type is not accidental, as RAW images absorb all the tiny details of a shot without compressing or altering the raw data. RAW files are high definition and great in size; hence, they’re typically converted before being distributed.

There’s a wide array of RAW image file types, so the format of your pictures will vary depending on the camera/program you use. The most popular extensions are:

  • CRW, CR2 (Canon); 
  • NEF (Nikon); 
  • CR, K25, KDC (Kodak); 
  • PEF (Pentax); 
  • ARW, SRF, SR2 (Sony); 
  • DNG (Adobe).

RAW image file type

 

Vector File Formats

As discussed earlier, vector image files are made up of equations instead of pixels. These file types grant full flexibility for resizing, as they maintain graphic quality regardless of the size. 

Vector files are rarer to come across since their application online is limited. But if you’re working with logos, icons, digital illustrations, or typography, vector file types will quickly become your best friends. So let’s explore them!

 

PDF (Portable Document Format)

PDF is another popular image file format belonging to Adobe. PDF files can be viewed and edited in the Adobe Acrobat application that also provides web services. This format can display vector and raster images, spreadsheets, text documents, and more. 

Because of its versatility and universal support, PDF is highly preferred for printing designs. That’s why you often see business cards, flyers, posters, magazines, or books in this file format. Besides, PFD documents are highly portable and easy to convert to other image file formats.

While the format is handy for manipulating text-based documents and infographics, it’s not the best option for image editing due to its limited toolset.

PDF image file type

 

AI (Adobe Illustrator Artwork)

When it comes to digital art creation, Adobe Illustrator is an industry leader. It provides a comprehensive drawing and editing toolkit to create complex vector illustrations from scratch. The software’s primary file format is AI, but you can export your designs in other common file types as well. 

AI is ideal for designs that need a lot of altering, as it allows the manipulation of any large or small detail in a vector graphic. It’s used for logos, artwork, covers, posters, and any other graphic design that requires careful planning and then scaling. 

Similar to other Adobe file types, AI is not supported by most image viewers and browsers. Thus, AI files are not fit for quick viewing or sharing unless they’re converted to other image file formats.

AI image file type

 

EPS (Encapsulated Postscript)

EPS is one of the most prevalent vector image formats specialized in creating high-quality graphics for print. It’s accepted by most graphic design apps and maintains graphic quality across all scales and programs. 

Even though most graphic design tools can read EPS, the format has been yielding its place to PDF and is now considered outdated by many graphic designers.

EPS image file types

 

SVG (Scalable Vector Graphics)

SVG is a vector image file type that has become quite popular on the web thanks to its ability to be compressed to small file sizes. As a vector graphic format, it’s fully scalable without losing quality and is often used for logo files. 

SVG files are compatible with most graphic software programs. Although it’s not meant for complex photos or illustrations, the web-friendly format is well suited for simple graphics and text-based files.

SVG image file type

 

So What’s the Right Type for You?

There are a number of factors that come into play when choosing an image file format that will satisfy your needs and ensure your graphics look the way you intend them to on your chosen platforms.

The first choice you have to make is whether you want to work with raster or vector file types. Keep in mind that if you plan to use your design in multiple sizes, you’ll need a vector image. But before publishing the image online, convert it to one of the browser-optimized file types like JPEG or WebP.

We hope you found this guide useful. If you’re looking for attractive designs for your blog, presentation, or print assets, have a look at our vibrant library of graphic templates that are optimized for various projects.

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