Why sites moved to WebP
Images are the heaviest part of most web pages, and on a mobile connection every kilobyte shows up as waiting. WebP was built to cut that weight without visibly changing the picture, using prediction techniques borrowed from video compression.
It also removed an old compromise. Before WebP, a site had to choose between JPG for photographs and PNG for anything needing transparency. WebP handles both, so a single format covers the whole page.
Where the speed gain matters
Search engines measure how quickly the largest visible element on a page appears, and on most pages that element is an image. Shrinking the images above the fold moves that measurement more than almost anything else you can change.
Compression is only half of it, though. Serving a 3000 pixel wide image into a 600 pixel slot wastes far more bandwidth than any format choice can recover, so resize to the size you actually display before converting.
When to keep the original format
- Form uploads. Indian portals accept JPG, occasionally PNG, and never WebP.
- Email attachments. Some clients will not preview a WebP for the recipient.
- Printing. Print services expect JPG or PDF.
- Archiving originals. Keep the source file. Converting is easy to repeat, recovering lost detail is not.
Frequently asked questions
How much smaller will my file be?
For a photograph, expect roughly a quarter to a third smaller than an equivalent JPG. For a graphic with transparency, the saving against PNG is often far larger than that.
Do all browsers support WebP?
Every current browser does, including Chrome, Safari, Firefox and Edge. Support has been universal for several years, which is why most sites now serve WebP by default.
Does WebP keep transparency?
Yes. Converting a transparent PNG to WebP keeps the transparent areas, which is the main advantage it has over JPG.
Should I convert images for a government form?
No. Upload forms in India expect JPG and will reject WebP. Use this format for websites and keep JPG for anything that gets submitted somewhere.
Will converting a JPG to WebP improve quality?
No. The detail the JPG already discarded stays lost. The benefit is a smaller file at the same visible quality, not a better looking image.
Is WebP good for a print job?
No. Print services generally expect JPG, TIFF or PDF. WebP is designed for screens and web delivery.