2026-10-02
Most "compress image" sites follow the same pattern as the PDF ones: you upload your pictures, a server shrinks them, and you download the result. TinyPNG is the best-known example. That is fine for a stock photo. It is less fine for a screenshot of a dashboard, a scan of an ID, or a photo with your home address in its location metadata. The images leave your machine before you ever see what the tool did to them.
iLoveDevTools's Image Compressor does the work in your browser tab instead. The image is decoded, resized and re-encoded by your own browser, and nothing is sent anywhere.
Quality (JPG and WebP). This is the lossy dial. On a 1600 x 1200 test photo (a 676 KB JPG made from smooth gradients and soft noise), the JPG output was 33 KB at 30% quality, 135 KB at 70% and 482 KB at 90%. WebP at the same settings came out at 22 KB, 90 KB and 423 KB. Real photographs have more fine detail than that test image, so expect different absolute numbers; the shape of the curve, where the last few quality points cost a lot of bytes for little visible difference, is the same.
Largest side. Capping the longest side is often the biggest saving of all, because a 4000 px photo displayed in a 800 px column is mostly wasted pixels. The same test photo dropped from 676 KB to 76 KB as a JPG at 75% quality when capped at 1200 px.
WebP. Switching format is the quickest win. The 3.87 MB PNG version of the test photo became a 95 KB WebP at 75% quality. WebP opens in every current browser, though some older apps and email clients still do not display it.
PNG colors. PNG is lossless, so a browser re-saving a PNG with every color intact does not make it smaller: the test photo went from 4,058,153 to 4,058,104 bytes, which is 0%. The real PNG savings come from reducing the picture to a palette. This tool does that itself with a median-cut color quantizer and a small indexed-PNG writer: the same photo became 792 KB at 256 colors, 496 KB at 64 colors and 278 KB at 16 colors, while a flat-color graphic (a logo-style image with 71 distinct colors) shrank from 26.7 KB to 7.3 KB at 256 colors with no visible change. Photographs show banding at low color counts, so use the before/after slider.
If a setting produces a file that is not at least slightly smaller than your original, the tool says so and does not offer the download. That happens more than you might expect: a flat-color PNG re-saved losslessly went from 26.7 KB to 28.7 KB, and a 16 x 16 icon converted to JPG more than doubled in size. In those cases you keep the original.
Compressed images are redrawn from pixels, so EXIF data such as GPS location, camera model and timestamps is not carried over, and any rotation stored in the orientation tag is applied to the pixels first. That is usually what you want before posting a photo publicly, but keep the original if you need the metadata. PNG and WebP keep transparency; if you choose JPG output, transparent areas are filled with white.
TinyPNG and similar upload tools. Their strength is a polished, tuned pipeline that many people trust for PNG and JPG. The trade-off is that the files go to their servers. Here nothing is uploaded, and you can batch many images into one .zip.
Squoosh. Squoosh also runs in the browser and is a genuinely excellent tool, with more codecs (including AVIF) and finer control over each encoder. If you need AVIF, or want to squeeze the last percent out of a single image, use it. This tool uses the browser's own JPG and WebP encoders and its own PNG palette code, so it offers fewer knobs, but it handles a whole folder at once with one set of settings.
If the images are private, or you have a batch to shrink for a web page or an upload limit, try the Image Compressor. If you want AVIF or maximum control over a single image, Squoosh is the better fit. To shrink images inside a document instead, Compress PDF does the same job for PDFs.