Does transparency survive?

Yes. WebP supports an alpha channel, and transparent areas convert across unchanged.

Should I use lossy or lossless WebP?

The quality slider controls this. At 100 the result is effectively lossless; lower values compress much further and suit photographs and illustrations rather than sharp-edged graphics.

Which browsers can display WebP?

All current ones. Chrome, Firefox, Edge, Safari and every major mobile browser have supported it for years.

How much smaller should I expect?

Lossless WebP is usually around a quarter smaller than PNG. Lossy WebP is frequently ninety per cent smaller, depending on the image.

PNG → WebP · runs on your device

Same image, transparency intact, a fraction of the weight

WebP does what PNG does, including transparency, in far less space. For anything going onto a website it is close to a free improvement.

PNG has been the default for web graphics needing transparency for two decades, which is why so many sites still serve megabyte-sized logos and illustrations. WebP replaced it on merit: lossless WebP is typically a quarter smaller than the equivalent PNG, and lossy WebP, which PNG has no equivalent of, is often smaller by ninety per cent while keeping the alpha channel intact.

Support is no longer a reason to hesitate. Every current browser reads WebP, including Safari since 2020 and Edge since 2018. The practical cases where PNG still wins are narrow: assets that must open in older desktop software, and images destined for print workflows that expect PNG or TIFF.

Page weight is worth caring about beyond the bandwidth bill, because loading speed affects how a page ranks in search and how many visitors stay long enough to read it. Converting the images is usually the largest single improvement available, and the least disruptive.

Questions

Does transparency survive?: Yes. WebP supports an alpha channel, and transparent areas convert across unchanged.
Should I use lossy or lossless WebP?: The quality slider controls this. At 100 the result is effectively lossless; lower values compress much further and suit photographs and illustrations rather than sharp-edged graphics.
Which browsers can display WebP?: All current ones. Chrome, Firefox, Edge, Safari and every major mobile browser have supported it for years.
How much smaller should I expect?: Lossless WebP is usually around a quarter smaller than PNG. Lossy WebP is frequently ninety per cent smaller, depending on the image.