I noticed that the image preview on the right-hand side tends to get cropped incorrectly when using the "snap grip to image" feature. For example, this image that says "Hello" is 64x40 pixels. After I snap the grip to the image, the preview on the right side is cropped to only show the "ell" part of "hello".
I am running a fresh install of Texturegrub and have not changed any settings from their defaults (to my knowledge).