Pictures resize and move at random?

Hi all,

I have a reasonably basic Excel sheet in use as a parts list which contains a few photos of components to allow the guys in the stores to identify some parts.

Unfortunately, seemingly at random, these pictures not only move but resize too, even when opened only on one pc (so screen size, resolution same etc) and sometimes next time I open the sheet they go back to original postion, sometimes not.

Looks like what I would imagine could happen if I was zooming in and out and they weren't fixed in place, but I'm not, and I can't find any way of fixing them to an absolute position on the sheet anyway.

Any suggestions?

Yep, I've got the box ticked for don't move or resize, but it still does both.

Could it have anything to do with using a laptop in a docking station with a bigger screen?