Image Comparison Slider
Compare two images side by side with an interactive slider.
How to Use
- Upload your original (before) image
- Upload your compressed or converted (after) image
- Drag the slider to compare quality differences
Tips for Comparison
- • Compare the same image in different formats (JPEG vs WebP)
- • Test different compression levels
- • Look for artifacts around edges and text
Frequently Asked Questions
What images should I compare?
The original file and its optimized version — for example a raw JPEG export next to the same image as WebP at quality 80. Both should have identical dimensions so the slider lines up.
Does comparing images upload them anywhere?
No. The comparison runs entirely in your browser; both files stay on your machine.
Why do compressed images look worse at some edges?
Lossy compression discards data first around sharp transitions — text edges, fine patterns, and high-contrast boundaries show artifacts before flat areas do. Drag the slider over those regions when judging quality.
Can I compare different sizes?
Technically yes, but the slider overlays them at mismatched scales, which makes quality judgement meaningless. Resize to matching dimensions first.