PNG and WebP can both handle transparent graphics, but their strengths are different. PNG is a mature lossless format with predictable behavior. WebP offers both lossless and lossy modes and was designed with efficient web delivery in mind.
Lossless graphics
For flat-color graphics, screenshots and interface assets, both formats can work well. The smaller result varies by image content and encoder, so measuring real output is more useful than assuming one format always wins.
Transparency
Both formats can represent transparency. This makes either one suitable for many overlays, icons and product cutouts where JPEG would not work.
Editing and interchange
PNG remains widely recognized by image editors, office software and design workflows. WebP is well supported in modern web environments but may still be less convenient in some older desktop workflows.
Website delivery
For a website, WebP is worth testing because it can reduce transfer size while preserving the visual result you need. For downloadable assets intended to be opened in many different applications, PNG may still be simpler.