Article

Can an AI Image Detector Check a Screenshot?

Yes, when the file is a JPEG, PNG, or WebP. The score is an estimate about that file. A screenshot, a resized preview, or an edited copy is not the same evidence as the original export.

Start with the file you have

The useful question is which file you are holding. These are different inputs, even when they show the same scene:

• Original export. The file a camera or a generator saved.
• Screenshot. A new picture of a screen. It can include a status bar, scaling, and a new file format.
• Messaging or page copy. A rendition an app or a site made, often resized and saved again.
• Resized preview. A smaller version made to fit a message or a layout.
• Crop or filter. Part of the picture, or the whole picture after color, sharpening, or smoothing.
• Partial edit. A real photo with a generated piece added, or a generated image with a real photo pasted in.

The checker can score any of those once the file is a supported image. The result belongs to the file you added. It does not reconstruct the one you do not have.

What a screenshot changes

A screenshot is not a copy of the original file. The device draws the screen into a new image, then saves that image. The new pixels can include interface, scaling, and the display’s color. The new file has its own encoding.

An embedded Content Credential is signed to the file it belongs to. C2PA’s deployment guidance says to avoid screenshotting or re-exporting through tools that remove metadata, and to keep the original export. Its technical guidance also says that a platform which changes resolution or quality often removes or breaks that record, even when the picture still looks the same.

A screenshot does not prove that every provenance signal is gone. C2PA describes a soft binding, such as an invisible watermark, that can sometimes still be found after a screenshot or a social-media rendition. A missing embedded record is not proof the image is real, and it is not proof that no other signal remains.

Real Image Check does not read watermarks or Content Credentials. How to tell if an image is AI-generated explains those signals, and when a publisher’s own verifier is the right tool.

Compression, resizing, and saving again

A detector looks at pixels. Saving the picture again changes pixels. JPEG compression discards detail and can leave block edges. Resizing rebuilds the picture at a new size. A second save can do both. A small preview from a message is a different file from the export it came from.

Research on other detectors shows why the change is real, and why it is not a rule you can borrow for every tool. In Fake or JPEG? (Grommelt, Weiss, Pfreundt, and Keuper, 2024), JPEG compression moved the results of the detectors they studied. Generated images were more often treated as ordinary photos when the training data had compressed photographs and uncompressed generated images. Heavier compression also changed how those detectors treated real photos. The direction and the size of the change depended on the detector and the data.

Community Forensics (Park and Owens, 2024) trained detectors with JPEG compression, resizing, blur, and other changes. Those models held up better than some earlier detectors, and the effect still depended on which change was applied. Neither paper is a test of Real Image Check. This site has not published how often a screenshot, a resize, or another save moves its own label.

Compression and resizing can change a detector result in either direction. They do not reliably hide a generated image, and they do not reliably reveal one.

Edits and mixed images

A crop throws away part of the picture. A filter, a denoise, or a sharpening pass changes the pixels that remain. A collage can put a generated face on a real street, or a real product into a generated room. Those edits can move a score toward AI-generated or toward a real photo. Which way depends on the edit and on the model. Real Image Check has not published a count of how often that happens.

A small change inside a mostly real photo is the harder case. This checker returns one score for the whole image. It does not outline a region, and it does not say which object was added. A score that leans toward a real photo can still belong to a picture with a generated patch. A score that leans toward AI-generated does not identify that patch.

What Real Image Check does with the file

The checker scores one image at a time. The file must be a JPEG, PNG, or WebP, up to 20 MB. Other types are not scored. If a phone saved a format the checker cannot open, export it once to JPEG, PNG, or WebP. Skip a filter, a crop, and a second save after that export.

The analysis runs in this browser. The image is not uploaded for analysis. Real Image Check does not upload or store the image, a preview, its file name, or the detection score. A recent check stays in this browser until you clear it or leave the page.

The checker does not name a generator. It does not read camera data, a watermark, or Content Credentials. The score uses the file you added, after that file is decoded. It does not read the file’s compression setting as a separate fact.

Before the score, the checker scales the picture so the shorter side is 440 pixels, then uses a 384 by 384 square from the center. A small image is enlarged to reach that size. If either side is shorter than 32 pixels, the image is not scored. The checker is looking at that prepared view of the decoded pixels.

How to read the score

The score is shown from 0.000 to 1.000. A higher score leans toward AI-generated. A lower score leans toward a real photo.

• 0.65 or above: Likely AI-generated.
• Below 0.65: Likely a real photo.

Scores on the same side of 0.65 share that label. A result of 0.66 and a result of 0.99 say the same thing. A result of 0.64 is labeled likely a real photo, and it can still be wrong. The score is an estimate, not a probability or proof. On a screenshot or a recompressed copy, it is an estimate about that copy. For why another detector can disagree, see Why does the same image get different AI detector scores?

When the result matters

Ask for the original export when you can, and check that file rather than a picture of it. Do not screenshot a screenshot to try the checker again. If you have to convert the file, save it once as JPEG, PNG, or WebP.

Then read the label beside the image. Use the guide for visual clues and for checking where the image was published. If the result would change what you publish, pay, or believe, go back to the source. One score is not the whole answer.

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