Best Image Format for Websites: A Practical Guide
The best image format for websites depends on what the image shows. Photos, logos and screenshots each have a best match. This guide gives you a simple way to choose.
Use our free Convert Image tool to do this in just a few clicks. It runs in your browser, so your files stay private.
Key takeaways
- WebP is the best all-round choice for most website images.
- JPG is the safe fallback for photos, and PNG suits exact pixels.
- AVIF can be smaller still, but needs more effort and has less software support.
- Pick by image type, then check the real file size.
The quick answer
For most websites, use WebP. It gives small files for photos and graphics, and it keeps transparency. Keep JPG as a dependable choice for photos that will also be shared outside the browser, and use PNG when you need exact pixels in a master file. AVIF is worth a look if you already have a workflow for it.
Best format by image type
| Image type | Best format | Why |
|---|---|---|
| Photos | WebP or JPG | Smooth detail compresses very well |
| Logos and icons | PNG, SVG or WebP | Sharp edges and transparency |
| Screenshots with text | PNG or high-quality WebP | Text stays crisp |
| Large hero images | WebP or AVIF | Smallest files for the biggest images |
| Simple animations | WebP or video | Smaller than GIF |
The formats in one line each
- JPG: universal and good for photos, with no transparency.
- PNG: lossless with transparency, but large for photos.
- WebP: lossy or lossless, with transparency and animation, supported by all current major browsers.
- AVIF: often the smallest files, but slower to create and less widely supported outside browsers.
How format affects speed
Images are often the heaviest part of a page, so the format you choose has a direct effect on loading time. In comparisons published by Google, lossy WebP files are about 25 to 34% smaller than JPEG at the same measured quality (see Google’s WebP documentation). The real saving depends on each image, so measure your own files.
Faster loading helps visitors on slow connections and supports good scores on loading metrics such as Largest Contentful Paint.
When you need transparency
JPG cannot do transparent backgrounds. For logos, stickers and overlays use PNG or WebP. WebP usually produces the smaller file, so convert with PNG to WebP and check the edges on a light and a dark background.
Compatibility
All current major browsers display WebP and AVIF. The gaps are outside the browser: email programs, print services and some editors still prefer JPG or PNG. If your images are meant to be downloaded and reused, offer a JPG or PNG too.
How to decide in four questions
- Is it a photo or a graphic with sharp edges?
- Does it need a transparent background?
- Will it be shown only on your website, or also shared elsewhere?
- Which format gives the smallest file that still looks right?
A workflow that works
- Keep every original as a JPG or PNG master.
- Resize to the size you need with Resize Image.
- Convert website copies to WebP with Image to WebP.
- Check the sizes and look at the images on a real page.
Examples by site type
| Site type | Approach |
|---|---|
| Blog | WebP photos, JPG fallback if you need one |
| Online shop | WebP product photos, careful quality checks |
| Portfolio | High-quality WebP or JPG, check colours |
| Documentation | PNG or WebP screenshots |
Mistakes to avoid
- Saving photos as PNG.
- Choosing a format only because it is new.
- Deleting the originals after converting.
- Never checking how images look on a phone.
Go deeper
For a side-by-side look at the four formats, read JPG vs PNG vs WebP vs AVIF. For the most common pairings, see WebP vs JPG and WebP vs PNG.
A note on AVIF
AVIF often produces the smallest files, which is attractive for large hero images. It also takes more time to create, and fewer programs open it. If you adopt it, keep a WebP or JPG version too. AllWebP can read AVIF files as input and convert them with Convert Image.
Animated images
For short animations, animated WebP is usually smaller than GIF, and a short video is smaller still. Our converters handle still images, so for an animated file they use only the first frame.
Checklist before you publish
- Each image is in the format that suits its type.
- File sizes have been compared with the originals.
- Images look right on a phone and on a desktop.
- The original files are stored safely.
Frequently Asked Questions
What is the best image format for a website?
WebP is a strong default for most images. JPG and PNG remain good choices for compatibility and exact pixels.
Should I use AVIF?
It can give smaller files, but it takes more effort to create and fewer programs open it. WebP is the simpler choice.
Is PNG bad for websites?
No, but it is large for photos. Use it for graphics that need exact pixels, and convert big ones to WebP.
Do I need a JPG fallback for WebP?
All current major browsers display WebP, so a fallback is rarely needed for web visitors.
Keep reading
JPG vs PNG vs WebP vs AVIF compared: compression, transparency, animation and compatibility, with a simple guide to choosing the right format.
WebP vs PNG: Which Image Format Should You Use?WebP vs PNG compared: file size, transparency, quality, editing and compatibility, with a clear guide to choosing the right format.
WebP vs JPG: Which Image Format Is Better?WebP vs JPG compared: file size, quality, transparency, compatibility and when to use each. Learn which format is better for your images.