Image style settings for scaling an image What settings can I use for the image style module that will make all thumbnails in a gallery  of a consistent width and height? Thus, if an image's width is smaller than the thumbnail width when scaled, the width of the thumbnail remains consistent.
Have you tried the Scale and crop option ? Go to admin/config/media/image-styles/add add a new style and then select Scale and crop with, for example, 100px width and height. This will produce some square thumbnail with 100px sides.