Why WebP
A PNG screenshot is lossless and often heavy. WebP at quality 75–85 usually keeps text crisp at a fraction of the size, and current browsers, Notion and most CMSs accept it. The result panel shows the file size and the change against the original before you save.
Check the text at 100%
Open Compare to see the original and the WebP at actual pixels, and drag the handle across small text. If you see smudges around letters, raise the quality a few steps; if not, try lowering it.
When to keep PNG
Choose PNG for pixel-exact UI details and for images another platform will compress again. Choose JPEG where WebP isn't accepted.