preview window enhacment

Goal: make a beautiful and minimal background preview page that lets you see the majority of the image.

• fix removal of current background, revert to default, not sure how to fix
• - remove some obsolete stuff
• - Change expansion arrows to system ones, use right and down arrow
• - fix header to reveal previous work of transparent header
• - change big buttons to header (remove cancel for regular page navigation)
• - Add a delete button so we can delete pictures