Image issues

If you take a look at the link below, all of the wall decal images are cut off. I have tried to edit the media image and save the thumbnail so that it does not cut anything off, but it does not update this view. Is there a way that I can change how these images appear so they are not cut off on my website? Thank you!
http://www.mh-grafix.com/website/product-category/wall_decals/

My theme provider said this is an issue with the way wordpress shows images. Anyone know a way to fix this? Thanks!