Free tool

Compare images

Compare two images online with a before-and-after slider, side by side, as an overlay or as a difference image that highlights and counts every changed pixel—in this texture-pack example, 736 of 9,000 pixels (8.18 %). Free, with no sign-up or upload: your images stay in your browser.

Built by Justin Schuessler

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Before

After

The images stay in your browser. Nothing is uploaded.

Upload a Before and an After image. Then compare them with a slider, side by side, as an overlay, or as a difference image showing every changed pixel.

Example result

What image comparison shows you

Upload a before and an after image. Spot differences visually with the slider, side-by-side view, or overlay; difference mode highlights and counts every changed pixel. Here’s an example using the tool’s sample images:

Example: an autumn texture pack compared with the original

Input:

Two pixel-art landscapes, each 120 × 75 pixels. In the after image, the grass and leaves have changed color, and a new flower appears in the meadow. Difference mode, threshold 5%.

Before

After

Difference

Output:

Difference mode result in the example
Changed pixels	736 of 9,000 pixels
Share	8.18 %
Download	Full-resolution difference image as a PNG

The sky, sun, ground, and rock are the same in both images and appear dark gray in the difference image. Only what the texture pack actually changes lights up red. Your result will depend on your images, of course.

How it works

How to compare two images

Four steps from screenshots to a finished comparison, with no account or upload.

Step 1

Load images

Drag the Before and After images into the two fields, select files or paste screenshots with Ctrl+V. Use “Swap” to switch sides. The images are opened only in your browser.

Step 2

Select mode

Slider, side by side, blend or difference. In slider mode, drag the divider vertically or horizontally. In blend mode, adjust the opacity; in difference mode, adjust the threshold and color.

Step 3

Zoom and compare

Zoom up to 3,200% using the plus and minus buttons, Ctrl+mouse wheel or a two-finger gesture, then drag to pan the enlarged image. “1:1” displays each pixel at its original size, with sharp edges from 100%. “Fit” shows the whole image again.

Step 4

Save result

Download the before-and-after image, side-by-side view, overlay or difference image as a full-resolution PNG. In Slider and Side by Side modes, you can optionally add Before and After labels.

PNG export

Create and save a before-and-after image

Each mode has its own download. The PNG is created at full resolution in your browser, with no upload or watermark.

Before-and-after image

In Slider mode, the download splits the image exactly where the dividing line is. The PNG shows the line and, optionally, the Before and After labels.

Two images side by side

Side by Side puts both images in one file, with optional labels. If placing them side by side would make the image too wide for your browser, the tool stacks them vertically. There are always exactly two images; there are no collage templates.

Overlay

Both images overlaid, with the After image at the opacity you set using the slider.

Difference image

Changed pixels in your chosen color on a darkened grayscale version of the Before image, at the comparison's full resolution.

Difference images and PNG exports support up to 40 megapixels per image, or less on iPhone and iPad due to their lower canvas limit.

Use cases

What you can use image comparison for

From shader packs to compression tests: wherever you need to compare two versions of the same image.

Shaders and texture packs in Minecraft

Take the same screenshot with and without a shader or resource pack. The slider lets you compare lighting, water, and shadows directly, while 1:1 zoom and crisp pixel edges reveal even individual 16 × 16 textures.

Graphics mods and textures for FiveM

Compare vehicle textures, ReShade presets or Map Mods on your FiveM server. Difference mode shows which areas a new texture actually changes.

Test graphics settings

Low vs. Ultra, DLSS vs. FSR, anti-aliasing on or off: two screenshots of the same scene show whether a demanding setting makes a visible difference.

Mods before and after

Whether it's a lighting Mod, HUD Mod or Map update, the blend lets you gradually switch between the original and the Mod to spot even small changes.

Check compression artifacts

Upload the original and compressed versions. At a threshold of 0 %, difference mode shows every changed pixel; with some tolerance, it shows only visible artifacts.

UI and design changes

Compare two versions of a website, server menu or Discord banner. Moved elements and changed colors stand out immediately in the difference image.

Images too large for a quick comparison? Reduce file size with the image compressor

Four modes

Which mode should you use?

Slider

The divider shows the before image on the left or top and the after image on the right or bottom. Ideal for comparing lighting, colors, and sharpness. Use it vertically or horizontally with a mouse, touch, or arrow keys.

Side by side

Two panes with synchronized zoom and panning. Ideal when you want to see both images in full. On mobile, the panes are stacked.

Overlay

The after image overlays the before image at an adjustable opacity. Slowly blending between them reveals shifted or slightly changed areas.

Difference

Every changed pixel is highlighted in your chosen color and counted. The threshold filters out small differences such as JPEG noise. You can download the difference image as a PNG.

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FAQ

Frequently asked questions

Quick answers about comparing images, formats, sizes and privacy.

Drag the Before and After images into the two fields, select files or paste screenshots with Ctrl+V. Then choose a mode: Slider with a dividing line, Side by Side, Overlay or Difference. To try it out, “Try with sample images” loads two ready-made images.

No. Both images are opened only in your browser, and a Web Worker calculates the difference in the same tab. There is no upload, server or sharing link. The tool writes only settings such as mode, direction and threshold to the address bar, never image content.

Load both images, select “Slider” and place the divider where you want it. “Download before-and-after image” saves a full-resolution PNG with the divider and, optionally, “Before” and “After” labels. In side-by-side mode, you get both images next to each other in one file.

Choose Difference mode. It highlights every changed pixel in a color of your choice and shows the count and percentage. The threshold determines how much a pixel must change to count: from 0 to 50% of the color range, with a default of 5%. If the mode highlights changes you cannot see, the cause is usually lossy compression (JPG, WebP), scaling, color profiles or a one-pixel offset. Increase the threshold or compare lossless PNG screenshots.

JPG, PNG, WebP, AVIF and GIF; for animated GIFs, the first frame is used. The tool does not accept HEIC files, so export them as JPG first. Each file can be up to 40 MB. Slider, Side by Side and Overlay also work with very large images. Difference images and PNG exports support up to 40 megapixels per image, or 16.7 megapixels on iPhone and iPad. Above those limits, the tool shows a notice instead of freezing the tab.

The tool shows both resolutions and lets you choose: “Scale after to before” (default) stretches the after image to match the before image, which is useful for screenshots at different resolutions. “Align top left” overlays both images without stretching, which is useful if one was only cropped or extended. If their aspect ratios differ, the tool warns you about distortion when scaling.

Yes, right in your browser, with no app. Drag the dividing line with your finger, pinch to zoom, and drag to pan the enlarged image. In Side by Side mode, the two views are stacked vertically on your phone. Select images using your phone's file picker.

No. The tool compares the color values of both images pixel by pixel using an adjustable threshold. It does not use AI, detect faces or objects, or search the internet for similar images. It shows you exactly where your two images differ.

Any more questions?

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