Annoying problem where images randomly turn into red objects after I re-open flash

Hi

Just a very annoying problem. I have images which I have been broken to resize them to suit my design. What happens is that every now and then when I re-enter my flash movie these images turn red and I have to do the whole image imputing and breaking apart process once more…

very annoying and time consuming…anyone have any insight to why this happens and how it can be prevented?

Thanks

Eddie