Compress Images to a Target Size (JPG, WebP, PNG)

The quality slider is the direct control: lower values give smaller files and more visible artefacts. The preview above the results re-encodes one of your images as you move the slider, so you see the real output and its exact size rather than a guess. Pick the image to preview from the list when you load several.

Target size mode is for upload forms that demand a limit such as 200 KB. The tool encodes at the best quality first, then at a low one, and then searches between them for the highest quality that fits. If even the lowest quality is too big it shrinks the pixel dimensions in 15% steps and repeats. If the limit still cannot be reached, you get the smallest result and a note saying so. The third lever is the maximum size option: a 4000 pixel photo shown on a 1280 pixel wide page wastes most of its pixels.

A canvas can only write PNG losslessly, and re-encoding an already optimised PNG usually saves nothing. So PNG compression here works the way dedicated PNG optimisers do: the image is reduced to a palette of 256, 128 or 64 colours and written as an indexed PNG with transparency preserved. Flat graphics, screenshots and logos usually keep their look and shrink a lot. Photographs and smooth gradients can show banding, which is why you should compare the preview before downloading.

If compressing a file would not make it smaller, for example a PNG that is already tiny, you get the original file back unchanged and the row says so. For photos, converting PNG to WebP or JPEG is normally a far bigger saving than any PNG setting, so try the output format option too.

Everything runs in your browser, one image at a time, with a ZIP download for batches and a total before and after size for the whole run. Images up to 50 MB and 64 megapixels are accepted, and up to 100 files per run. The browser decodes each file, applies its EXIF orientation, redraws it and writes a new file, so the output does not contain the original EXIF data, GPS position or colour profile. That is a consequence of re-encoding, so check the output if you rely on it.

Repeated lossy compression degrades quality, so always compress from the original file, not from an already compressed copy. Colours can shift slightly for images with a wide-gamut profile because the result is plain sRGB. Animated GIFs are reduced to their first frame.