Step by step
- Open the image compressor and drop several photos in at once, or choose many files from the file picker.
- Pick the size limit that each photo should fit under, and the output format.
- If a form asks for a pixel size, choose the longest side under the options.
- Start. The photos are processed one after another and you download one zip with all of them.
Each photo gets its own limit
The size you pick applies to every photo separately, not to the total. If an email limit applies to the total of all attachments, divide it by the number of photos first. For example, ten photos that must fit under two megabytes together need about two hundred kilobytes each.
Technical details
How it works in your browser
A single background worker in your browser handles the photos one at a time, so memory use stays low even for a large batch. For each photo it searches for the highest quality that fits under the limit, and lowers the pixel size only if quality alone cannot reach it.
The zip is created in your browser too, with no extra compression because JPEG and WebP files are already compressed. The zip library is only loaded when a batch finishes.
Tips for good results
Use the same preset for photos with similar content. If one picture looks too soft, compress it again alone with a larger limit. Photos that are already smaller than the limit are returned unchanged, unless you asked for a smaller pixel size.