Compress JPG, PNG, and WebP images. Selected file contents are processed locally in your browser.
Local-first compression
Adjust the quality slider to balance file size and visual clarity. Everything happens in your browser—file contents are not intentionally uploaded by this tool.
Images are compressed in your browser. File contents are not intentionally uploaded by this tool.
The image compressor reduces file size by decoding the selected image in your browser and re-encoding it with a smaller output target. For JPG and WebP, the quality setting controls how much visual detail the browser encoder is allowed to trade for a smaller file.
When you drag an image into the compressor, your browser uses the HTML5 Canvas API to decode the image data. When you adjust the quality slider and hit "Compress," the browser re-encodes that data into your chosen format (JPG or WebP) using its native encoding engine. Selected photo contents are processed locally in your browser, and ConvertUnlimited does not provide a server-side upload endpoint for this processing flow.
Compression does not improve image quality and it does not guarantee a smaller file in every case. Some already-optimized images, transparent PNGs, or files converted at very high quality may stay similar in size or grow. Review the before/after size and visual preview before downloading.
Unoptimized images are often the primary cause of slow website performance. Compressing your images is essential for several reasons:
Different file formats use different methods to reduce size. Choosing the right one depends on your specific needs:
JPEG is the standard for digital photography. It uses "lossy" compression, meaning it discards some image data to achieve significant size reductions. It is universally compatible but does not support transparency.
PNG uses "lossless" compression, which preserves every pixel exactly as it was. This makes it ideal for logos, icons, and text-heavy graphics. While it supports transparency, PNG files are typically much larger than JPEGs or WebPs. Note: Browser-based compressors generally cannot perform "lossy" PNG compression; use WebP if you need transparency with a small file size.
WebP is a modern format that provides both lossy and lossless compression. It typically achieves 25-35% smaller file sizes than JPEG at equivalent quality and supports transparency like PNG. It is the best choice for modern web performance.
The quality slider determines the aggressive nature of the compression algorithm:
Working with dozens of images at once? Keep these performance tips in mind:
Compress JPG, PNG, and WebP images in your browser to reduce file size for websites, email, content workflows, and storage cleanup.
Add images, choose an output format and quality level, compare the result, then download individual files or a ZIP. Use Image Resizer before compression when dimensions are too large, and Metadata Remover when you need a separate metadata cleanup step.
For JPG and WebP, yes: lossy compression removes some information to reduce file size. At recommended quality levels, the difference is often hard to see at normal display sizes, but text, fine lines, and screenshots can show artifacts sooner than photos.
If you convert a highly compressed JPG into a PNG, the file size will grow because PNG is a lossless format designed to preserve data, not discard it.
This tool works in all modern browsers supporting the HTML5 Canvas API, including Chrome, Firefox, Safari, and Edge.
Files are processed locally where supported. Review the Trust Center for the processing model and the Privacy Policy for public-site privacy boundaries.