What this tool does
Convert a local image to PNG, JPEG or WebP and compare output size before downloading.
How to use it
- Choose a local PNG, JPEG or WebP file up to 25 MB and 40 million pixels.
- Choose the output format. Quality applies to JPEG and WebP, not PNG.
- Convert, compare the preview and actual file size, then download the result. Changing an input clears the previous download.
Formula and method
The browser decodes the image, draws it to a canvas and encodes the selected supported format.
Worked example
Try WebP at 85% and compare its actual byte size with the original.
Useful for
- Preparing a web image
- Comparing image formats
- Checking file size before publishing
Limits and notes
Browser codec support varies. Re-encoding removes most metadata and may change color or transparency; inspect the result.
Frequently asked questions
Will the converted file always be smaller?
No. Size depends on the image, format and quality. Compare the original and converted sizes before downloading.
Is my file uploaded?
No. Decoding and conversion happen in this browser. Keep the original and inspect color, transparency and details in the downloaded copy.