I used to just save everything as PNG because it "looked better" and never thought about it further — until I uploaded a folder of product photos to a website and watched the page take eight seconds to load. Every photo was a 4MB PNG that should have been a 400KB JPG. The format you pick isn't a cosmetic choice; it directly decides how big your files are and how your images actually look.
Here's the thing nobody explains clearly: these three formats aren't competing versions of the same idea. They solve different problems. Once you understand what each one is actually doing, picking the right one takes about two seconds.
Lossy vs lossless — the core idea
JPG is a lossy format. When you save a JPG, the compression algorithm throws away image detail it judges you won't notice much — subtle colour gradients, fine texture — to make the file dramatically smaller. That detail is gone permanently once saved; you can't get it back by "un-compressing."
PNG is lossless. Every pixel you started with is exactly what you get back. Nothing is discarded, which is why a PNG of a busy, detailed photo is so much larger than the equivalent JPG — it's not allowed to cheat by throwing anything away.
WebP is the newer entrant, and the reason it's genuinely useful is that it supports both modes. It can compress lossy (like JPG, but generally more efficiently) or lossless (like PNG, also generally more efficiently). At an equivalent visual quality, WebP files are typically 25–35% smaller than JPG and significantly smaller than PNG.
When to actually use each one
Photos — JPG or WebP. Photographs have complex, continuous tonal variation that compresses well under lossy algorithms, and the human eye doesn't easily notice what's missing. A family photo, a product shot, a landscape — JPG or WebP, not PNG.
Anything needing transparency, or sharp edges and text — PNG. Logos, screenshots, icons, graphics with flat colour blocks and crisp text edges. Lossy compression tends to introduce visible fuzzing and colour banding around sharp edges — the "JPG artifact" look you've probably noticed around text in a badly saved image. PNG keeps those edges perfectly clean, and it's the only one of the three that reliably handles transparency the way most people expect (a see-through background for a logo, for instance).
Modern web delivery — WebP. If you're publishing to a website and don't need to support genuinely old software, WebP is usually the best default: smaller files than JPG for photos, smaller files than PNG for graphics, with transparency support in both modes. Browser support is now near-universal — every major browser has supported it for years — so the old worry about WebP images not displaying for visitors is largely a non-issue today. The remaining caveat is really old desktop software (an outdated image viewer or editor) rather than browsers.
The tradeoffs, honestly stated
PNG's honesty about not throwing anything away is also its weakness — for a photo, a PNG can easily be 5–10x larger than a well-compressed JPG of the same image, for a difference most people can't actually see. If you're emailing or uploading dozens of photos, that adds up fast.
JPG's weakness is visible compression artifacts if you push the quality too low, and it has no transparency support at all — a JPG background is always opaque. It also degrades a little more each time you re-save it (more on that in a related article), so it's not ideal for images you'll be editing repeatedly.
WebP's weakness is really just that it's newer, so some older tools, email clients, or print workflows may not handle it gracefully, and if you need maximum compatibility with software from a decade ago, JPG and PNG remain the safer universal choices.
A simple rule of thumb
Photo going on a website → WebP, with JPG as the fallback. Photo you're emailing to someone who might open it in whatever came with their old laptop → JPG. Logo, screenshot, or anything needing a transparent background → PNG. That covers the overwhelming majority of real situations.
If you've got a batch of images in the wrong format, our Image Converter converts between JPG, PNG, WebP and BMP right in your browser — upload a batch, pick the output format and quality, and download them all as a ZIP. Nothing is uploaded to a server; the conversion happens locally using your browser's own image engine.