add a back/return, home and clear buttons

[ghost]

there is currently no way of returning to the previous screen or to the main screen when comparing an image. you can do it with the phone's buttons but it would be way faster and easier if there were buttons built in the program. you could put them on an empty corner.

there is also no "clear" button to remove an image. it would be nice if there were clear buttons for each image slot and a "clear all" to clear them both

[endolith]

Or is there a setting to tell the OS to not auto hide its buttons?