Which image file format is best for photos and graphics? And what do you need to know when converting from one to another? Learn about image types and conversion in our complete guide to image file formats.

Most of us don’t need to concern ourselves too greatly with image file formats. We take a picture on our smartphones or cameras, and perhaps post it online, and then we simply keep it on a computer, hard drive, or in the cloud for safekeeping.

But when it comes to uploading images online, using graphics, or archiving our creations, it pays to understand the strengths and weaknesses of the different formats available, and the kinds of images for which they may have been specifically designed.

Why do image formats matter?

At a basic level, understanding image formats helps you to maintain image quality. Whether an image is just for yourself or destined to be seen by others, you’ll clearly want it to look as good as possible – particularly if it’s designed to represent your brand.

It’s also important as some image types aren’t as widely supported as others, and so they won’t be usable or viewable everywhere. Furthermore, some files support certain features that allow them to be displayed correctly, or edited at a later date, while others may not.

Another important reason concerns efficiency. Understanding file formats means understanding files sizes, which helps you to send and store images efficiently. This also affects load times for your website’s pages, which has a knock-on effect on both user experience and SEO.

In this article, we’ll run through the main image formats used today, and explain their pros and cons, before we take a look at the things you should bear in mind when converting an image from one format to another.

Best file formats: At a glance

JPEG (.jpeg) Widely supported and used online, with small file sizes making it very efficient. Compression artifacts can be an issue, however, and it’s not ideal for graphics.
PNG (.png) Designed for graphics and widely supported online. Can preserve transparency layers, unlike most other formats. Not as efficient as JPEG and not designed for real-world images, but a good choice for photograph/graphics composites.
TIFF (.tif) Great where maximum image quality is required and for archiving. Can be saved with or without lossy compression, although