Picture handling: hide the pictures before deleting

Because of the way deleteLater() is implemented, the pictures need to be
hidden, otherwise they might stay around at the wrong time (e.g., when
printing).

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Picture handling: cleaning up the mess

We had pointers to data structures on the stack which we frequently
reallocated. These data structure contain basically a filename and an
offset. We then create a hash of the pointers to those datastructures with
the filename being the key. And then we passed those pointers around
through a Qt model(!!!) only in order to then later look up by filename
what the offset might be.

I am at a loss for words for the lunacy behind this design.

How about we just remember the offsets and pass the integers around?

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>