This is something that happens fairly often in CC 2014. An image that was placed previously and displayed correctly suddenly stops everything when I display the page it's on and at the bottom of the screen it says "Reading IMAGE NAME" over and over and over. The only way out is to force quit. This is yet another maddening CC 2014 bug!
I just had it happen. After force-quitting, I opened the same file and did NOT get the "Reading IMAGE NAME" over and over and over. The inconsistency of this application is driving me insane!