Sean,
You can put a picture in a comment.
Create the comment, then right click its borderFormatColours & Lines
(?)Filloption at the bottomPictureBrowse for your picture.

NickHK

"Sean" ...
After entering a comment in a cell, a small red mark appears in the upper
right corner of that cell and when you move your mouse over it, it
displays
the contents of the comment.

Can I input a picture somewhere and then when the mouse goes over the cell
a
picture displays rather than the comment?

Thanks,

Sean