PNG, JPEG or WebP is checked by file signature before decode.
Resize or compress one image
Choose a file, set the output, inspect the preview and byte change, then download only the current verified result.
A simple, checkable workflow
No empty success panel is shown. Download stays locked until the generated bytes reopen with the requested format and dimensions.
Use width and height, or a percentage. Keep aspect ratio unless stretching is intentional.
Review dimensions, bytes, preview and SHA-256 values before download.
What the result means
The quality control is an encoder hint. Lower values often reduce bytes, but exact results vary by browser and image.
The quality control is hidden because Canvas PNG export does not use it. A resized PNG may still be larger.
SHA-256 identifies exact input and output bytes. It does not prove visual quality, ownership or safety.
Does this tool crop an image?
No. With aspect lock on, one dimension updates from the source ratio. With it off, the requested width and height stretch the image. No crop or fit claim is made.
Does it preserve metadata or color profiles?
No guarantee is made. Canvas re-encoding commonly removes source metadata and does not guarantee ICC profile preservation.
Can it resize animated images?
No. Animated PNG and WebP inputs fail closed because a still-image export would silently discard frames.
Where does the image go?
The image bytes are read by this browser's local file and Canvas APIs. The renderer has no network request that sends the selected file, filename, pixels or hashes.
Method and sources
The tool checks the file signature and structural dimensions, decodes the image, applies Canvas2D resizing, encodes the selected format, reopens the output, verifies its signature and dimensions, and computes SHA-256 over exact bytes.