Compression and transparency
PNG is always lossless. It stores every pixel exactly, which keeps screenshots, text, and logos sharp no matter how many times you edit them. It also supports full alpha transparency, so cutout images keep clean edges over any background you place them on.
WebP can be lossy or lossless and also supports alpha transparency. Its lossless mode is designed to pack graphics more tightly than PNG, so the same logo or screenshot often comes out smaller without dropping pixels. Its lossy mode handles photographs the way JPG does.
Support and everyday workflow
PNG opens everywhere: every browser, operating system, printer, and design tool accepts it. WebP is supported by all current browsers and most apps, but older desktop software may refuse the file. Anything that leaves your control is safer as a PNG copy.
The two formats also behave the same where it counts for graphics. Text and hard edges stay clean in PNG, and they stay clean in WebP lossless mode while taking less space. If a viewer only sees the finished image, the format rarely matters to them.
Choosing and converting
Use PNG as your archive and exchange format for graphics, and WebP when the image will be displayed online and download weight matters. If a site or form has a size limit, WebP often clears it without touching the pixel dimensions.
Conversion in both directions is straightforward and runs in the browser. WebP lossless keeps every pixel from the PNG; WebP lossy may not, so keep the original if the graphic will be edited again. Neither direction adds detail that the source file never had.