That's not exactly the happiest MM ever looked on film, now is it? I'm guessing based on the waterfall behind here that this photo was from when she was filming Niagara Falls. She injured her ankle at some point during filming on that movie, so perhaps that accounts (in part at least) for the glum expression (again, if this image is from around that time). ♥ Jessica
It is a costume test photo, so I suppose she didn't bother looking sexy or happy. But perhaps you're right about her ankle. She did wear plaster for some weeks.