Sorry, I think I didn't explain myself well enough. :)
We had Build 183 in use since some weeks ago. In Build 183, in the Report Tree on the left side of the screen you had little camera icons besides every snapshot in contrast to the cube symbol besides OLAP Analysis.
In Build 188 now, you still have the cube symbols for OLAP Analysis, but the camera icon for snapshots has disappeared. I figured out that the underlying image "snapshot.gif" in sub-folder "images" is still existing in Build 188, but unfortunately it is not showing in the Report Tree anymore. Is there a way to bring it back to the GUI?