You can snapshot any object singly even if other controls overlap or lay under it. Another advantge is that the object does not need to be visible when getting a snapshot. It can even be on a different card.
Richmond's right about groups, I forgot about that. The object export is handy there too if there are images or controls in the group you don't want to capture; you can single out one control inside the group and snapshot that without worrying about the other controls underneath or a background color set on the group.
If I were playing with this image and wanted to save the result without the button I can export only the image object. I did this from another card in the stack. The yellow border is an effect applied to the group.