Compare Images
Upload two images and find every pixel-level difference instantly.
One platform for all your image editing needs
Free online apps to edit, convert, compress, and enhance images in your browser
Pixel-Level Image Comparison
Compare images side by side and detect every difference with precision.
Spot Every Difference
The image comparison tool analyzes two images pixel by pixel and generates a visual diff highlighting every change between them.
9 Comparison Methods
Choose from Butteraugli, LPIPS, SSIM, PSNR, MAE, RMSE, AE, NCC, and PDC to match the analysis method to the use case.
Detailed Error Reports
Get per-channel error counts, difference percentages, and file metadata tables alongside the visual diff output.
Choose the Right Comparison Method
The image comparison tool offers 9 analysis methods, each suited to different tasks. SSIM measures structural similarity the way the human eye perceives it, making it ideal for image quality assessment. PSNR calculates the peak signal-to-noise ratio and is commonly used to evaluate compression quality.
For pixel-level counting, AE reports the absolute number of different pixels, while MAE averages the difference across all pixels. RMSE provides a root mean square error metric for statistical analysis, and NCC measures normalized cross-correlation to find how closely two images match. Adjust the threshold from 0 to 100 to control sensitivity.
Butteraugli is the default. The threshold applies only to the pixel-based methods.
Check the Impact of Compression on Image Quality
Compare images before and after compression to measure exactly how much detail is lost. Upload the original file and the compressed version, then let the tool generate a visual diff that highlights compression artifacts. The diff image shows precisely where boundaries, gradients, and fine textures have changed.
The results table reports per-channel error counts for blue, green, and red, plus the total pixel difference as both an absolute count and a percentage. Use this data to find the optimal compression level where file size drops without visible quality loss.
When to Compare Images
Common scenarios where the image comparison tool saves time.
Design QA
Compare design mockups against final renders to verify that every element matches the approved layout.
Compression Quality Check
Measure how much detail is lost after compressing an image. Find the optimal compression level with measurable data.
Version Tracking
Compare two versions of a photo or graphic to track exactly what changed between revisions.
Supported Image Formats
Compare images in any common format. The tool accepts JPG, JPEG, PNG, WebP, GIF, BMP, and TIFF files. Upload two images in different formats and the tool handles the conversion automatically before running the comparison.
Customize the diff highlight color to red, green, blue, yellow, orange, violet, black, or white. The visual diff image clearly marks every region where the two images differ, and the comparison report can be exported as a downloadable PDF for documentation and sharing.
Compare 2 images in any of these formats, then export the report as a PDF.
How to Compare Images Online
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Upload two images
Drag and drop or browse for the two images to compare. Supported formats include JPG, PNG, WebP, GIF, BMP, and TIFF.
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Choose comparison settings
Select a comparison method such as SSIM or MAE. Pick a highlight color and set the sensitivity threshold.
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Run the comparison
Click Start to analyze both images. The tool generates a diff image with differences highlighted in the chosen color.
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Review the results
View the diff image, per-channel error counts, and difference percentages. Export the report as a PDF.
Compare Images FAQ
How does the image comparison tool work?
The tool analyzes two uploaded images pixel by pixel using the selected comparison method. It generates a diff image that highlights every region where the images differ. The results include per-channel error counts for red, green, and blue, plus the total difference as both an absolute count and a percentage.
What image formats can I compare?
The image comparison tool supports JPG, JPEG, PNG, WebP, GIF, BMP, and TIFF. You can upload two images in different formats and the tool converts them automatically before running the comparison.
Which comparison method should I use to compare images?
SSIM is recommended for most tasks because it measures structural similarity the way humans perceive quality differences. Use PSNR to evaluate compression quality with a single numeric score. For strict pixel counting, use AE to get the exact number of pixels that changed. MAE and RMSE provide averaged and statistical error metrics for research and reporting.
Can I compare images of different sizes?
For the most accurate results, both images should have the same dimensions. If the images have different sizes, prepare them by resizing to matching dimensions before uploading. Use the Img2Go Resize Image tool to adjust both images to the same width and height.
Is the image comparison tool free?
Yes. The image comparison tool is free to use with no signup required. You can compare images online directly in the browser. A cross-project free trial allows 2 comparisons per day.
How do I compare images to check compression quality?
Upload the original uncompressed image as the first file and the compressed version as the second. Set the comparison method to SSIM or PSNR and click Start. The diff image shows where compression artifacts appear, typically at object boundaries and fine textures. The error percentage tells you how much the compressed image deviates from the original.
Are my images safe when I compare them online?
Yes. All processing is automated with no human monitoring. Your files are accessible only through unique, non-guessable URLs. The servers are located in the EU and comply with GDPR regulations.
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