Lossless pixels and lossy options
PNG is a lossless raster format. It is dependable for sharp graphics, screenshots and assets that need exact pixels, but a photo saved as PNG can be very large.
WebP supports both lossless and lossy compression plus alpha transparency. A lossy WebP may be much smaller, though it can soften text or create halos around edges. Browser tools may expose lossy quality controls rather than a true lossless mode.
Use the image itself to decide
For photographs, test WebP at the dimensions and appearance your page needs. For logos and interface icons, compare the alpha edges and any thin details; PNG may remain the safer master.
Neither format removes the need for responsive sizing. An image with far more pixels than its display box can waste bandwidth regardless of encoding.
Frequently asked questions
Which format supports transparency?
Both PNG and WebP support alpha transparency.