resizing pictures do not stay in proportion

[faithsecr]

I am using Publisher 2007. After inserting a picture, if I try to resize the
picture by clicking and dragging the corner circles, it does not stay in
proportion. The help files says it should, but it doesn't. (Dragging an
open circle at a corner resizes the image proportionally. If you drag one of
the side circles, the image grows or shrinks disproportionately, as shown
here.) I know it will stay in proportion if I hold the shift key, but I
didn't have to do that in the previous version of Publisher that I had. Is
there a setting I need to change? Any ideas? Thanks!

 

[faithsecr]

I think I just figured it out--the picture I was working with was not one I
had just added, but was from the Publisher 2000 file I converted to 2007.
When I deleted that picture and inserted it again in a new frame, it resized
correctly.