Stackbench Image Compressor & Resizer
Decodes your file, redraws it on a canvas at the size you choose, and re-encodes it with the quality you set — showing the before and after byte counts so you know the trade-off you made.
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How to use
- Drop one or more images onto the box, or select them from your device.
- Set a maximum width in pixels and pick an output format and quality level.
- Read the saved-size number for each image and adjust until it looks acceptable.
- Save the results individually, or use Save all to download every processed image.
Frequently asked questions
Is it really private?
Yes. Encoding uses the canvas API inside your browser, so no upload request is ever made. You can confirm this yourself by disconnecting from the network after the page has loaded.
Why did my PNG get larger, or lose its transparency?
PNG is lossless, so recompressing it rarely saves space; the gains come from shrinking the dimensions. Choosing JPG or WebP discards the alpha channel, so keep PNG for images that need transparency.
What quality setting should I use?
Start around 80 for photographic JPGs, where most of the size reduction happens with little visible loss. Below about 60, banding and smearing around edges become obvious, especially on dark gradients.
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