John Mueller indicated yesterday on Twitter that, when Google already indexed an image, that can take several months before this file is again crawled, for example if it were modified meanwhile. The reason is simple according to John: the images change in general much less often than pages HTML and require less cooling. The deadline between two crawls can thus prove very long.

Morals of the history: when you publish images, pay attention well so that the first version put online is most final possible because it is likely to remain a long time available in the engine dedicated to the images of Google… Let us note that does not relate to the first indexing (initial discovery of the file) which, for its part, is often very fast. It is then that the process slows down…