zeus - 6:14 pm on Oct 4, 2012 (gmt 0)
There was a image update trust me and Google dont say that often when there is a google image update, Im even not sure if they ever had.
The problem is not safe search on and off for most, thats always the first thing to check, they did have a problem a few years ago, where they have filtered to many images without any reason.
About normal google update, yes before Panda it did not influence the google image ranking, but over the last year to 2 the ranking on the web search has some effect on rankings, somewhere I have also seen them say that, but thats some time ago.
Ohh one more thing martin, not always is it you can see the images rotate, sometimes its just the url that changes, the image is the same.