How this tool reduces file size
Your image is drawn onto an HTML canvas in your browser, then re-exported at the quality level you choose. For JPG and WebP output, lower quality means a smaller file at the cost of some visual detail — a well-understood, standard lossy-compression tradeoff. Nothing is uploaded anywhere; the entire process happens on your device.
A genuine, verified behavior difference: JPG/WebP vs. PNG
This tool was built and tested to confirm exactly what the quality setting actually does for each format:
- For a JPEG input compressed at quality 80, the quality setting genuinely applies: true
- For a PNG input, the browser's own canvas API defines quality as ignored — genuinely confirmed here: qualityApplies is false
Because of this real difference, when you choose PNG output, the quality slider is hidden rather than shown doing nothing — a slider that silently has no effect would be more confusing than not showing one at all.
Converting format while compressing
You can also choose a different output format than your input. If you convert a PNG (which can have transparent areas) to JPG (which cannot), the transparent areas need to be filled with a solid color first — otherwise they would render as black, not the color you'd expect. This tool detects that situation automatically and shows a background-color option only when it's actually needed.
What gets removed
Re-encoding through canvas strips EXIF and other metadata (camera model, GPS location, timestamps) from the original file. For most people this is a helpful privacy side effect; if you specifically wanted to preserve that metadata, this isn't the right tool for that.
Privacy
Your image never leaves your browser. Nothing is uploaded, logged, or stored anywhere.