How to Compress Images Without Uploading Them

Learn how image dimensions, format and quality influence image size.

Why images get large

Pixel dimensions, colour information, file format and compression settings all influence the final file size. A camera photo can contain far more pixels than a webpage needs.

Resize before aggressive compression

If an image is much larger than the size at which it will be displayed, reducing its dimensions can cut file size significantly while preserving acceptable visual quality.

JPEG quality

JPEG uses lossy compression. Lower quality usually means smaller files, but excessive compression can create visible artifacts. Preview the result and choose a practical balance.

Process locally

The ToolZeroo image compressor is designed to process the selected image in your browser. Use the Image Compressor to test different quality settings.