What image file types retain quality online without a large file size? Discover the best image formats for the web, no matter how you’re using them.
We know you have a better grasp on file formats than Derek Zoolander and Hansel McDonald. However, choosing the best image format for the web becomes more complicated with each passing year.
Every file type stores information about an image in a different way. Some formats retain quality no matter how many times we duplicate the image, while we can save other formats on a transparent background for ease of use. The file format you select for an image will dictate the overall quality, the size of the image file, and the context in which you can use the image. You’ve probably heard of PNGs and JPGs before, but there are a few more you might be missing.
Before you decide what file format works best for your current project, learn what types of files can reduce image size while retaining high-quality online.
Raster vs. Vector File Formats
Before we delve into specific file formats, let’s differentiate between the two most common types of image files — vector images and raster images.
Vector Images
Vector images are composed of paths and curves dictated by mathematical formulas. Specialized graphic design software like Adobe Illustrator produces vector paths and images.
Using mathematical equations to produce images will keep file sizes small. Vector images can be scaled up endlessly but still render and print crisply.
Regardless of the scalability of vector images, most images online are raster images. The reason is simple. Most vector file formats aren’t compatible with standard web applications.
Raster Images
Raster images contain bitmaps that contain maps of pixels. Pixels are the smallest addressable square components of the file that are combined to create two-dimensional images. That sunset shot you uploaded to your portfolio? It’s a raster image. That professional headshot on your website? It’s a raster image.
The more pixels in a file, the smoother and more higher-quality it is. If you zoom in on a raster image, you’ll see the pixels. Curves become jagged the more you zoom in on an image.
The battle you face with raster images is straightforward: How do you maximize the quality of the image, or increase the number of pixels, without making the file size too large to use online?
Learn more about the differences between vector and raster files in our quick overview.
Web-Friendly File Formats
Now that you know you’ll need raster images for most online uses, you’re probably asking: “Which image file type is best?” There’s no “right” answer. Each file format comes with unique benefits, limitations, and best use scenarios.
JPEG
Joint Photographic Experts Group developed JPEG files, hence the name. When file type extensions had a three-character limit, these files were called JPG files. Now, JPEG is more common.
Coders developed JPEG files to share photographs online, while keeping file size manageable.
- Advantages — JPEGs have a smaller file size than other raster image file formats. The file size allows your page to load quickly and delivers a better user experience. JPEGs are compatible with most applications, are highly versatile, and constitute the most common image format on the web.
- Disadvantages — JPEGs are known for their “lossy” compression. Every time you compress a JPEG image to reduce the file size, it suffers a loss in quality. The algorithm that compresses JPEGs will find pixels that are nearly the same color, or value, and group them into tiles. When you save the new image, you lose that data forever.
PNG
PNG is an acronym for Portable Network Graphics. This file type is optimized for logos, graphics, and graphs. You can also save a photograph as a PNG, and will sometimes notice it’s a higher-quality than a JPEG.
- Advantages — PNGs reduce image size without any loss in quality. You can save, edit, and reopen these files without them degrading, which is a substantial benefit. PNGs also allow you to save images with transparent backgrounds, making them ideal for web design.
- Disadvantages — PNGs are larger in file size than JPEGs. The image compression utilized by PNG files still reduces image size, but not to the degree of a JPEG. PNGs also work best for images that use fewer than sixteen colors.
GIF
GIF stands for Graphics Interchange Format and represents an image format with a specific use case. You’ve sent GIFs to co-workers on Slack or to family group texts in the context of an animated clip from a TV show or movie. A GIF file can be animated and is best for small graphic images that require movement.
- Advantages — GIFs showcase animations on your website that can’t be accomplished with CSS. Limited color images that are small in size perform well in GIF format.
- Disadvantages — GIFs only support 256 colors, and are the wrong choice for showcasing complex images. GIF files also take up more space than files that contain static images.
SVG
SVG — Scalable Vector Graphics files — are vector files you can use in web design. These vector images support animation and interactivity.
- Advantages — SVGs are resolution-independent and create dynamic, crisp images that display well on any platform. SVGs are lossless files that retain their quality.
- Disadvantages — SVGs are substantially larger in file size compared to other image formats. Reserve them for top-tier websites and uses.
Choosing the Right Image Format for the Web
Now that we’ve filled your brain with technical knowledge, let’s consider real-world applications. When you’re meticulously creating your digital footprint, we recommend specific formats for these common types of web images.
Blog Posts
Blog posts on your website should load quickly to improve SEO and provide users the best experience possible. Readers won’t magnify photographs and images on your blog, so stick with the JPEG format for your blog. The number one priority is keeping your image file sizes down, and in most cases the quality loss won’t be noticeable.
Online Portfolios
Depending on the types of images you’re showcasing and the performance of your website, you’ll either use JPEG or PNG files. JPEGs are optimized for photography, and depending on the design of your portfolio, the lossy compression may not be an issue. PNG files will roughly double in size, but if you’re a graphic designer or are showcasing large images, the switch to PNG will be worth the trade-off in load time.
Animations and Icons
Your professional website will feature eye-catching icons and graphic elements, especially if you’re a designer. PNGs are the gold standard for web icons, graphics, and text. Turn to GIFs for small, simple animations. However, SVGs should be your go-to for interactive websites and animated web videos.
Cover image via pikcha. Image via Dimitri Vaindirlis. Mockup via BoxerX.
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