How to Compare Two Photos and Highlight Differences

Have you ever stared at two seemingly identical screenshots trying to figure out why one file size is bigger than the other? Or tried to compare a mock-up design to the implemented website to ensure it's pixel-perfect? This guide will show you exactly how to automate that process using Diff Guru's Image Compare tool.

Step 1: Prepare Your Images

For the best results, your images should be the same dimensions. If you are comparing a website screenshot, ensure you captured the viewport at the same resolution. Diff Guru accepts standard formats like PNG, JPG, WEBP, and GIF.

Step 2: Load the Images

1. Go to the Image Compare page.
2. Drag your first image (the "Original" or "Reference") into the left box.
3. Drag your second image (the "Changed" or "New") into the right box.

Step 3: Select the "Difference" View

Once both images are loaded, look at the view options below the images. Click on Difference.

This is the magic mode. The tool compares the RGB value of every single pixel.

• Dim/Grayscale areas: These parts are identical.
• Bright Red areas: These pixels are different.

If you see a completely dim box, congratulations! Your images are identical. If you see red speckles, those are differences—perhaps compression noise or slight shifts in position.

Step 4: Verify with "Slide" or "Fade"

Sometimes the "Difference" view is too abstract. You know that pixels changed, but not what the object is. Switch to Slide mode.

Drag the handle back and forth over the red areas you spotted in the previous step. This animation helps your brain understand the context of the change (e.g., "Oh, the logo moved 5 pixels to the right").

Conclusion

Comparing photos doesn't need to be a manual "spot the difference" puzzle. By using the right tool and workflow, you can highlight changes instantly, ensuring your designs are accurate and your files are correct.