Image Quality Comparator
Compare an image against a compressed preview and see the size saved — in your browser.
Image Quality Comparator is a browser-based image tool on ImgToolsBase. Compare an image against a compressed preview and see the size saved — in your browser. To use it, upload or drop your image and view the result directly in your browser — no signup and nothing to install.
How this tool works
What it does
Shows the original beside a compressed JPG/WebP preview and reports the size saved.
Scope
Original-vs-compressed, not a two-image comparison; the download is the preview.
Transparency
JPG flattens it onto a colour; WebP can preserve it when the source has an alpha channel.
Privacy
Compression and preview happen in your browser; nothing is uploaded.
Image Quality Comparator in your browser
Image Quality Comparator shows your original image next to a compressed preview at a quality and size you choose, so you can judge how much quality is lost for the file-size saving. The downloadable result is that compressed preview, not the untouched original.
Pick a compression quality, an optional maximum width, and JPG or WebP output. The tool encodes the preview, reports the percentage size saved, and shows both versions side by side.
It compares the original against a compressed version of itself rather than two separate images. JPG output flattens transparency onto a background colour, which is disclosed in the result.
How to use Image Quality Comparator
- Upload an image into Image Quality Comparator.
- Set the compression quality, optional max width and compressed format.
- Click Process to build the compressed preview beside the original.
- Review the size saved and quality, then download the compressed preview.
Why use Image Quality Comparator
View the original and a compressed preview side by side at your chosen quality.
Reports the percentage smaller the compressed preview is than the original.
The download is the compressed preview; the original is untouched.
JPG or WebP output, with a JPG background colour for transparency.
Common uses for Image Quality Comparator
Find a quality setting that balances size and visible quality.
See how small an image gets before committing to it.
Judge JPG vs WebP for a given image at a target width.
Spot compression artefacts against the original.
Frequently asked questions
Does Image Quality Comparator compare two separate images?
No. It compares your original against a compressed version of the same image. To compare two different files side by side, use the Compare Images tool instead.
What exactly do I download from Image Quality Comparator?
The compressed preview — the JPG or WebP version produced at your chosen quality and width. Your original file is not modified.
Does Image Quality Comparator report objective metrics like SSIM?
It reports the percentage file-size saving and the before/after dimensions and quality. It does not yet compute SSIM or PSNR scores.
How does Image Quality Comparator handle a transparent PNG?
If the compressed format is JPG, transparency is flattened onto the background colour you choose. WebP can preserve transparency when the source image has an alpha channel.
Is my image uploaded to compare quality?
No. Compression and the side-by-side preview are generated in your browser; nothing is sent to a server.
Related image tools
Tools that pair well with Image Quality Comparator.