It's possible that one of your security products has started blocking things for some reason.
Have a look through for anything that relates to pictures/images and disable the options one by one until things start to work.
Failing that I would suggest turning off the popup/ad blocking options one by one until they start to work.
Of course, if none of this works, you can always turn them all back on again
It might not seen like it's likely that they're the cause, it's worth eliminating them though
