Hi… this was mentioned in this thread http://forum.eyewire.org/discussion/comment/559 … but I haven’t seen any reply. As soon as I updated to Frefox 13 (Mac OS X 10.7.4) I started to get this annoying behaviour. As I move through the image stack I get flashes of blank screen… more and more the faster I go. Just wanted to reflag it in case it can be fixed 
This is not something that can be fixed in the short term.
Unfortunately the latest FF flickers when the source of an image object is rapidly changed. We are looking at switching to WebGL for the 2d view which would resolve this, but this is a large overhaul and will take some time to get working.
In the mean time, WebKit based browsers do not seem to have this issue. Depending on how bothersome you find it, you could try Chrome, Chromium, Safari (on macs), or a number of other browsers that use the WebKit engine.
Sorry for the inconvenience