Checking AI images after compression
Compression often makes a file smaller and easier to share. It can also remove creation details and weaken the image patterns a detector uses.
Two kinds of evidence can change
A conversion can discard embedded metadata or signed provenance. Pixel compression can alter fine details that a visual detector examines. These effects vary by format and tool.
Keep the original and the copy
If you control the file, check both versions. A different score does not prove either version was misread; it shows the detector is sensitive to the changed bytes.
When the only copy is small
A thumbnail, messenger copy, or screenshot may leave too little reliable information. In that situation Not Sure is often the responsible outcome.