I would assume it is the same as setting a flag to close-open a subpage, I would think it would be up to four flags based on which gesture you use. Hopefully, DemoPad will chime in on this one. But that is how I would look to do it.
I wonder if you would need four different images outside the normal non-highlighted image?
Say something like:
Highlight_Up
Highlight_Down
Highlight_left
Highlight_Right
So when you swipe in any one of the directions above it would activate and highlight just that section based on your swipe. Thoughts?