Any way to do this?

[Kay C Lan]

on mouseUp
  copy image "my1stimg" and image "my2ndimg" and image "mynthimg"
end mouse up

As it sounds like some or all of your images may not be on the same
card as the button, you will need to use the full address of the
image, ie image "mynthimg" of cd "my1stCard"

Interestingly you can also:

set the clipboardData["objects"] to image "my1stimg" and image
"my2ndimg" and image "mynthimg"

but if you use the paste command nothing happens. If you use copy,
then when you use paste the images will be pasted.