There are examples suggested here that have been established in other cases. An image used as evidence in one article is re-used in another article as evidence for something else. An image is used twice in one article as evidence tor something unrelated.

The images are often rotated or otherwise lightly disguised. There are people who are very good at spotting this kind of manipulation but not everyone can do it, particularly if it involves combing past publications. It could readily be supported by machine-based analysis.