Image 'When clicked on' effect for custom GUIs

Status
Fixed
Issue description

It would be cool to add procedures for clicking on images to custom GUIs, because when using images for backgrounds of GUIs having the normal button often look out of place.

It would also help stylise custom GUIs more, and could be used to create secret buttons that are invisible :)

Issue comments

I have come up with a limited way to do this by hiding a button behind an image, However, it is difficult to do with many images due to their shape, and some images can be too small for this.