Thumbnail Help

When I convert images to thumbnails it seems to “cut” off the top of the head on each photo I want to use. I was thinking that that I could choose the area of the thumbnail that I would like to use (much like when I set up my Gravatar) – but I couldn’t find such an option.

Here is a link to the images that I am having trouble with – http://happynewyou.com/what-people-are-saying – I am not using any plugins to upload or edit the photos. I’m just using the Edit Image and Advanced Image Settings. Any insights are most welcome. Thank you.