Compress Images: Quality Control With a Size Estimate

Shrink PNG, JPEG, WebP, AVIF, and PDF files with a quality slider and a live estimate of the resulting size. Heuristic prediction appears instantly; a sample encode refines it after the slider settles. No files leave your browser.

How to Compress Files

Use the converter in Compress mode when input and output formats match:

Upload Files: Drop images or a PDF you want to shrink
Match the Format: Keep the same output format (for example JPEG → JPEG) to enable Compress
Move the Quality Slider: Lower quality for smaller files; higher quality for sharper results
Read the Estimate: Compare input size to the predicted output before you run
Compress & Download: Process locally and save the smaller file

Why the Size Estimate Matters

Guessing compression results wastes time. img2img shows what to expect:

Instant Heuristic

As soon as you change quality, a fast estimate updates so you can explore settings without waiting.

Sample Refine

After the slider settles, a short sample encode tightens the prediction for a more accurate preview.

Images & PDFs

Recompress photos or re-encode PDF pages at a lower quality when you need a smaller document.

Format Conversion Too

Need a different format instead? Switch the target and convert with the same quality controls.

Supported Formats

✓Images: PNG, JPEG, WebP, AVIF, GIF, TIFF, HEIC, ICO, SVG (as supported)
✓Documents: PDF recompression and PDF ↔ image conversion
✓Ebooks: EPUB compress with optional grayscale — see Compress EPUB
✓Privacy: Client-side only — files never upload to a server

Ready to Compress Images?

See the size estimate first — then download smaller files

Compress Files Now