Tool 014 / files / free / runs locally
Image Compressor
Shrink JPG and PNG images using a quality slider. Compression runs entirely in your browser via the Canvas API, so your file is never uploaded to a server. Compare original and compressed sizes side by side.
Drag & drop an image here, or click to choose a file.
JPG, PNG, WebP. Stays on your device.
How it works
This compressor shrinks JPG, PNG, and WebP images by re-encoding them as JPEG at a quality level you choose. It reads your file with FileReader, draws it onto a hidden canvas at its original pixel dimensions, then exports the canvas as a JPEG with the selected quality. The whole process happens in your browser, so your images are never uploaded anywhere.
JPEG quality is a lossy trade-off: lower quality discards more high-frequency detail and produces a smaller file. The slider runs from 10 to 100 percent. The tool shows the original and compressed sizes side by side along with the percentage saved, so you can dial in the smallest size that still looks acceptable. The default of 75 percent is a good starting point for photos.
Because output is always JPEG, transparency is not preserved: a transparent PNG gets a solid background where it was see-through. For photographs that is usually fine and the savings are large; for logos or screenshots with sharp edges and transparency, JPEG may not be the right format.
How to use it
- Drag an image onto the drop zone, or click it to choose a file.
- Move the Quality slider to balance file size against visual quality.
- Compare the original and compressed previews and the percentage saved.
- Click Download compressed to save the JPEG to your device.
Worked examples
Input: A 2.4 MB JPEG photo at 75 percent quality
Output: A compressed file around 0.6 MB, roughly 75 percent smaller, with little visible difference.
Photographs compress well because JPEG suits continuous-tone images.
Input: A PNG screenshot with crisp text at 60 percent quality
Output: A smaller JPEG, but text edges may show faint ringing artifacts.
Sharp-edged graphics are where JPEG quality loss is most visible.
Edge cases and limits
- Output is always JPEG, so PNG transparency is flattened onto a background and is lost.
- The image keeps its original pixel dimensions; this reduces file weight by re-encoding, not by resizing. A huge image stays huge in pixels.
- Very large images are held in a canvas in memory, so extremely high-resolution files can be slow or fail on low-memory devices.
- Re-compressing an already-compressed JPEG adds generation loss; compress from the highest-quality source you have.
Common mistakes
- Compressing a logo or icon with transparency and being surprised the transparent area turned into a solid color.
- Pushing quality very low to save bytes, then shipping visibly blocky images. Check the preview at the level you pick.
- Expecting smaller pixel dimensions. This tool re-encodes; it does not downscale resolution.
Frequently asked questions
Will my image be uploaded?+
No. Everything happens inside your browser tab. We don't have a server endpoint that accepts image uploads, so there's literally no place for your file to go.
Which file types are supported?+
Any format your browser can decode as an image (JPG, PNG, WebP, GIF first-frame, etc). The output is always a JPEG to maximize compression. Use a higher quality slider for images with sharp edges or text.
Why is my PNG bigger after compression?+
If you started with a small PNG that uses few colors, re-encoding it as JPEG can actually be larger. For tiny PNGs (icons, screenshots with text), keep the original.
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