I got a web site design in PSD file from a web-designer. All element s there snap to guides, which is handy when I make a selection to copy an element of design to a PNG file: guides make my selection precise.

One button there has two states: normal and hover. Both states contains of several layers. So I am trying to copy both states as PNG files in order to make a nice button in html.

The problem is that both states have shadow effects, which go beyond the layers' edges, i.e. when I try to select a button my selection (snapped to guides) does not include an outer part of the shadow.

How do I make a precise selection of the button state in such situation?