Compare Image Differences Online
Spot visual changes instantly with a clear, side-by-side diff.
Upload both images to start comparing
Images are processed locally in your browser whenever possible. If local processing isn't supported or fails, we automatically complete the job on our servers - no action required. Compare JPG, PNG, WebP, AVIF, GIF, and HEIC files with smart sensitivity controls. No account required.
Why Use FastImageTools for Image Comparison
Local-first processing
Most checks run directly in your browser for speed and privacy.
Instant visual verdict
See if two images are identical, safe, noticeable, or significantly different in seconds.
Completely free
Compare single files or batches without sign-up, subscriptions, or watermarks.
Pixel-level analysis
Use sensitivity and filter controls to focus on real changes instead of noise.
How to Compare Two Images
- 1
Upload both images
Upload JPG, PNG, WebP, AVIF, GIF, or HEIC files you want to compare.
- 2
Choose comparison settings
Choose intent, sensitivity, and filters to match your format and use case.
- 3
Review and download the diff
Download the difference map and decide whether quality changes are acceptable.
Browser-Based vs Cloud Comparison
FastImageTools (local-first)
- Image comparison runs in your browser whenever possible.
- Instant feedback without waiting for queue-based processing.
- Good for everyday checks and most web-image workflows.
- Free to use with no watermark on results.
- Can work with limited connectivity when local execution is available.
Typical cloud tools
- —Files are typically uploaded before processing starts.
- —Performance depends on upload bandwidth and server load.
- —Usage caps and file-size limits are common on free plans.
- —Advanced comparison features are often paywalled.
- —No internet connection usually means no comparison.
Example Difference Result
Image A
6.2 MB
homepage-hero.png
Image B
6.1 MB
Minor visual changes
Supported Formats
JPG
Best for photos. Great for checking compression artifacts and subtle quality loss.
PNG
Best for UI assets and transparency. Useful for pixel-perfect regression checks.
WebP
Common web format with strong compression. Compare quality before and after export.
AVIF
Modern high-efficiency format. Validate visual impact at aggressive compression levels.
GIF
Palette-based format. Useful for checking banding, dithering, and color shifts.
HEIC
Mobile-first format. Verify edits and exports before sharing across platforms.
FAQ About Image Difference Checking
Can this detect small quality loss after compression?+−
Is it safe to compare private images?+−
What is the maximum file size?+−
Can I compare many image pairs in batch?+−
Can it compare lossy and lossless formats together?+−
Which format is best for web quality checks?+−
What is the difference between local and cloud comparison?+−
Are images uploaded to a server?+−
Related Tools
Continue your workflow with tools that help fix or optimize issues found during comparison.
Compress Image
Reduce file size and check quality after compression.
Image Optimizer for Web
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Image Format Inspector
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Metadata Viewer & Editor
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Image Merger & Stitcher
Combine multiple images into one final composition.
Image Splitter
Split one image into tiles or sections for layout workflows.