it just distorts the image. i'm actually shocked that such a basic function isn't included. Neither copying a image with its background intact, nor resizing the canvas without slicing all the images in it.
Edit: WOW, Found it. How strange. Bug maybe? If I select the image with ctrl+a (only one layer.) and paste it it gets the white background. but if I manually select and paste it, the transparant background is preserved. Strange...
Edit 2: No thats not true, infact. If I copy a small ammount over. The transparancy is preserved. If I copy a larged ammount, it doesn't Why is taht?