What version of Acrobat or Reader are you using?
In Acrobat and Reader XI you can use the "Selection Tool for Text and Images" - which you can find right next to the hand tool. If it's not there, right-click on the toolbar, go to the "Select&Zoom" category and add it to the toolbar.
With that tool selected, you just select the image, right-click and select to copy.
In Acrobat, you can also use the Tools>Content Editing>Edit Text and Images tool to select the image, then copy.
Karl Heinz Kremer
PDF Acrobatics Without a Net
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