import custom images as buttons

You can use custom image in 2 ways. 1. As premade button background by clicking "Image Button" at top right corner of the "Button" tab. But you cannot do any special effects like gloss with this option. This is mostly to add some simple text. 2. As texture. Choose a premade button, and at the "Button" tab, there is a "Type: Colors" Change Colors to Texture and choose your own image and adjust the special effects from there. This is probably what you wanted to do. But you're right that you can't resize/rotate/crop the custom image at will. You can only adjust the width/height percentage and the tiling.