Picking an image format is one of those decisions people make on autopilot — "photos are JPEG, everything else is PNG" — which is a reasonable rule of thumb, but it misses the format that usually beats both, and the specific reason PNG sometimes produces genuinely enormous files.
JPEG: built for photos
JPEG uses lossy compression tuned around how photographic images actually look — smooth gradients, complex color, no sharp hard edges. It throws away image detail the eye is less likely to notice and compresses what's left, which is why a JPEG photo can be a fraction of its uncompressed size while still looking essentially identical. That same lossy approach is exactly why JPEG is a poor choice for screenshots, logos, or anything with flat colors and hard edges — the compression artifacts (blurring, blockiness) show up much more obviously against sharp lines and solid color fields than they do in a photo.
PNG: lossless, and it shows in the file size
PNG doesn't throw anything away — every pixel comes back exactly as it went in, which is why it's the right choice for screenshots, logos, diagrams, and anything needing a transparent background (JPEG has no transparency support at all). The cost is size: a PNG of a genuinely photographic image, with all its fine color variation preserved losslessly, can be several times larger than an equivalent JPEG that most people wouldn't be able to tell apart at a glance.
WebP: usually the actual winner
WebP supports both lossy and lossless compression in one format, plus transparency (something JPEG can't do at all), and its lossy mode typically produces meaningfully smaller files than an equivalent-quality JPEG. For most images — including photos — WebP at a comparable visual quality beats JPEG on file size, and it beats PNG by a wide margin on anything photographic that needs transparency. The one real trade-off: it's newer, so a small share of older software and some email clients still don't handle it — worth checking your actual audience before making it your only format on something that can't afford to break.
A quick way to decide
- Photo, no transparency needed, broad compatibility matters most — JPEG.
- Screenshot, logo, diagram, or anything needing transparency — PNG, or WebP if your audience supports it.
- Anything where file size matters and you control the viewing environment (your own website, an app) — WebP, usually the smallest result at a given visual quality.
Using the tool
Our Image Compressor supports all three formats — JPEG, PNG, and WebP — with an adjustable quality setting, and always returns the original file unchanged if the compressed version would end up larger, so you never lose ground by trying.
Try it here: Image Compressor.