The three most common image formats on the web — PNG, JPEG, and WebP — aren't interchangeable. Each uses a fundamentally different compression strategy, which means each is genuinely better for certain kinds of images and worse for others. Picking the wrong one doesn't just waste bandwidth; it can visibly degrade image quality or bloat your page load time.
JPEG: lossy, built for photos
JPEG uses lossy compression tuned for photographic content — smooth gradients, complex color variation, no hard edges. It throws away detail the human eye is less sensitive to (especially in color, more than brightness) to achieve small file sizes.
That same strategy makes JPEG a poor choice for anything with sharp edges or flat color regions — text, logos, line art, and screenshots with UI elements. Compression artifacts show up as visible "ringing" around hard edges and blotchy color banding in flat areas, because the algorithm wasn't designed for that kind of content.
JPEG also doesn't support transparency at all.
PNG: lossless, built for precision
PNG uses lossless compression — every pixel of the original is preserved exactly, with no quality degradation regardless of how many times you re-save it. This makes it the right choice for logos, icons, diagrams, screenshots, and anything with text or sharp edges, where JPEG artifacts would be visually obvious.
PNG also supports full alpha transparency (not just an on/off transparent pixel, but partial transparency for smooth edges), which is why it's the default for icons and UI graphics.
The tradeoff: for photographic content, PNG files are dramatically larger than an equivalent-quality JPEG — often 5-10x — because lossless compression can't exploit the same perceptual shortcuts lossy compression can.
WebP: modern, and genuinely both
WebP is a newer format (developed by Google) that supports both lossy and lossless compression modes, plus alpha transparency, in a single format. In lossy mode it typically produces 25-35% smaller files than an equivalent-quality JPEG; in lossless mode it typically beats PNG too, though by a smaller margin.
The practical catch has historically been compatibility — some older software and email clients don't support WebP — but browser support has been effectively universal for years now, which is why most modern websites default to WebP (or the similar AVIF) for web images and keep PNG/JPEG only for cases where a file needs to work outside a browser context.
Quick decision guide
Photo for the web, size matters: WebP (lossy), fallback to JPEG.
Logo, icon, screenshot, or anything with text/sharp edges: PNG, or lossless WebP if you know the destination supports it.
Need transparency: PNG or WebP — never JPEG.
Maximum compatibility, format needs to work everywhere (print workflows, older software, email): JPEG for photos, PNG for graphics.
Try it
GlaeKit's Image Converter converts between PNG, JPEG, WebP, AVIF, BMP, and ICO entirely in your browser, and the Image Compressor lets you dial in quality with a live preview — both process files locally, nothing is uploaded.
Frequently asked questions
Is WebP always better than JPEG and PNG?
In terms of file size for equivalent visual quality, generally yes. The main reason to still use JPEG or PNG is compatibility with software or workflows outside the browser that don't support WebP.
Why does my screenshot look blurry after saving as JPEG?
JPEG's lossy compression is tuned for photographic gradients, not the sharp edges and flat colors typical of UI screenshots and text. Save screenshots as PNG or lossless WebP instead to avoid visible artifacts.
Does converting PNG to JPEG lose quality even at 100% quality setting?
Yes, unavoidably — JPEG is fundamentally a lossy format, so any conversion into it discards some data even at the highest quality setting, though the loss may be imperceptible at 100%.
Can I convert a JPEG back to a lossless PNG to "fix" it?
No — once JPEG compression discards data, it's gone. Converting to PNG afterward will losslessly preserve whatever quality loss the JPEG step already introduced; it can't recover the original detail.