I tried to search on a few images and this is what I got (in my own theme and in the default theme - 1.2.1):

1. When the search result covers more than the number of images per page, the page navigation shows page 1,2,3, etc, but clicking 2,3 and the rest always brings you back to page 1.
2. When I remove the $firstPageImages = normalizeColumns('2', '6'); to get rid of the transition pages (in case of also searching for folder names) I can't get to the other pages at all.

Please try the nightly build or (tomorrow) the 1.2.2 release.