I don't think it's meant to work as you expect. It does not, as far as I know, associate the picture number with the picture's actual file name, just numbers them sequentially as you add them. So if you you remove one then later add it back,  it has no way of knowing that it was there before so just gives it the next number. Also when you remove a picture it does not renumber the ones following it. Only if you delete all the pictures and save/reopen, the first picture added will be picture 1 again.

 

You can also change 'Picture 1', etc if you wish, highlight it in the box, overwrite with your own description, press enter. Again, though, if you delete a pic and insert it back in, as Excel does not know it is the same pic, it will give it the next Picture number and not the name you gave it.

 

It may be possible to write a macro that, for example, gives each picture a name corresponding to its file name, (so each would be uniquely named, even if added/removed then added back again) but I can't help you with that. If you post on the MS Office/Works board, one of the Excel experts may be able to advise further.

 

 

Thanks for your help--you have confirmed what I was finding.