Why WebP exists
For years the web had two imperfect choices. JPG compressed photographs well but could not do transparency. PNG handled transparency and sharp edges but produced enormous photographs. Sites carried both and picked one per image.
WebP was built to cover both cases in a single format. It compresses photographs more efficiently than JPG, supports transparency like PNG, and handles animation as well, which is why it has quietly replaced all three formats across much of the modern web.
Choosing a target for WebP
Because WebP is more efficient to begin with, you can aim lower than you would for a JPG and get a comparable result. A hero image that would need 200KB as a JPG often looks equally good at 130KB as a WebP.
For page speed, the images above the fold matter most. Those are what a visitor waits for, and what search engines measure when they score your loading performance. Compressing those aggressively is worth more than optimising everything below.
Practical notes
- Keep a JPG fallback for sharing. WebP displays fine in browsers but can confuse older desktop apps and some messaging clients.
- Do not convert back and forth. Every round trip through a lossy format removes detail permanently.
- Serve the right dimensions. Compression helps, but sending a 3000 pixel image to a 600 pixel slot wastes far more than compression can recover.
- Animated WebP is different. This tool works on still images only.
Frequently asked questions
What makes WebP smaller than JPG?
WebP uses prediction techniques borrowed from video encoding. It guesses each block from its neighbours and stores only the difference, which is far more efficient than describing every block independently the way JPG does.
How much smaller is WebP in practice?
For photographs it typically saves a quarter to a third compared with a JPG of similar quality. For flat graphics with transparency the saving against PNG is often much larger.
Does WebP support transparent backgrounds?
Yes. It handles transparency like PNG while still compressing like JPG, which is why it has replaced both formats on many websites.
Can I use WebP on a government form?
Usually not. Most upload forms accept only JPG and PNG. Convert the file before submitting rather than assuming WebP will be accepted.
Do all browsers display WebP?
Every current browser does, including Safari, Chrome, Firefox and Edge. Very old software and some desktop image viewers still do not, which is the main reason to keep a JPG copy for sharing.
Is there a lossless version of WebP?
Yes, WebP supports both lossy and lossless modes. This tool uses the lossy mode, since that is what allows an exact size target to be met.