OK, it must have been something in my config file. If I launch emacs -Q I can't reproduce the behavior and scrolling seems to work just fine (any idea? Could be any package I suppose..). I can't really reproduce the line-move error either in this mode. It does show up occasionally but I haven't figured out how to explicitly trigger it thus far.
What I have figured out however, is that scrolling using page up/down still produces funky behavior. To reproduce set cursor at end of buffer, press page-up, buffer jumps to beginning rather than scrolling over image. Press page-down several times, cursor gets stuck after first page-down scroll.