Pictures with same format won't print the same size

I have an Excel table with pictures in it in one column, one for every row. (See attachment)

When I look at them directly in the Excel table, everything is as it should.

The pictures in the rows 7 and 8 (identified as #4 and 5 in the B column) are of the same format than the others (give or take a few tenth of a millimeter!), and have the same properties, but when I print the page (or view print preview), these two figures are resized and are now clearly smaller that the others.

Anyone can guess as the solution for this?

Thanks!

Annie

I think I have part of the solution, but I still need help:

These pictures are gouped figures, and one of them had a figure that was not grouped with the others. Once I grouped the figures, and ensure the properties were ok, the print size was ok. However, I cannot find anything wrong with the other pictures. How can I find if I have "ghost" images, other than displacing the main figure (that's how I found the first one, but still cannot see anything wrong with the others...)?