WEBP vs PNG: Choosing the Right Format for Transparent Images
PNG has been the default format for transparent images for so long that it's easy to reach for it automatically. WEBP supports transparency too, though, and usually does it at a meaningfully smaller file size — which makes the choice between the two less obvious than it used to be, especially for anything destined for a website where load time matters.
Both handle transparency — the difference is efficiency
PNG's alpha channel transparency has been reliable and universally supported for decades, which is exactly why it became the default. WEBP supports the same kind of alpha transparency, but its compression is generally more efficient — a WEBP with transparency is typically smaller than an equivalent PNG while looking visually identical, which is the core reason WEBP has been gaining ground specifically for web use, where every kilobyte affects how fast a page loads.
Where PNG still has the edge
Compatibility is PNG's real advantage. Some older software, certain email clients, and a handful of platforms and content management systems still don't handle WEBP smoothly, whereas essentially anything that opens an image at all can open a PNG. If a transparent image is going somewhere you don't fully control — an email attachment, a document that might be opened in unpredictable software, a platform with unknown upload requirements — PNG remains the safer default specifically because you can't be certain WEBP will be read correctly on the other end.
Where WEBP's smaller size actually matters
For website graphics specifically — logos, icons, UI illustrations, anything with a transparent background that loads as part of a page — WEBP's smaller file size directly improves page load speed, which affects both user experience and, for many sites, search ranking. This is the context where switching from PNG to WEBP tends to be an unambiguous win: you control the destination (your own website), modern browser support for WEBP is now very broad, and the file size savings compound across every image on every page load.
A practical way to decide
For your own website's graphics, where you control the environment and speed matters: WEBP, since the compatibility risk is low and the performance benefit is real. For anything going to an unknown destination — an email, a document, a platform you don't control: PNG, for the guaranteed compatibility. If you're not sure which a specific destination expects, PNG remains the failsafe choice; you can rarely go wrong sending PNG, whereas WEBP occasionally causes a problem somewhere unexpected.
PNG to WEBP and WEBP to PNG handle the conversion directly in your browser, preserving transparency in both directions, so switching a specific image between the two takes seconds once you've decided which one the destination actually needs. The image converter covers the rest of the common format pairs if you're working across more than just these two.