Preview is quite a powerful little photo editor in its on right.
It will create
instant (multiple) +alpha channels+ cutting out backgrounds (or manually lasso a image and cut out background.) Save, select all and copy and paste onto a new photo,
re-size and
position the pasted image. PNG format works well for this.
Without going into a tutorial you can reference these pages for some partial idea:
http://books.google.com/books?id=DnebYWwwoqQC&pg=PA390&lpg=PA390&dq=usingpreview+to+cut+paste+alpha+channelphotos&source=bl&ots=dQbWerekeZ&sig=3pgSnurGPegoRz3rNNW1fw9WV2k&hl=en&ei=RNUbTb7 GMImqsAO7w5GaDw&sa=X&oi=book_result&ct=result&resnum=8&ved=0CEcQ6AEwBw#v=onepage &q&f=false
Make sure the tool bar is open on your
Preview image (pill button upper right) to be able to see all the tools, the
select in particular for the drop down menu. You may have to drag the image larger to expand the tool bar across the top.
I will admit Preview lost some vital functions when it went from Leopard to Snow Leopard, a real disappointment.
Hope this helps.
