Images in Main Page Boxes will not display correctly

We are trying to use MinaMaze for a site our non-profit uses. It is a great template, but is very frustrating regarding the images that go in the boxes on the main page. No matter what I do to the images, some go into the boxes perfectly although they are very large and other are cropped small. This occurs even when I take the images that do not post correctly amd use Photoshop to make them the exact same size as the ones that do. Very frustrating. Can someone help?