Open the .png file with Preview > click the box drop down located on the top of the window > click instant alpha > select the outer part of the image by clicking and dragging in one spot to another just a little bit (it may take some getting used to).
Now, the background that you want transparent should all be highlighted. Just click delete, and it will be transparent. If the instant alpha tool doesn't catch some parts of the background, you can use the rectangular selection or the circular selecting, and then delete the highlighted area.
Answers
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… move your ball layer above that transparent one
save/export as a .png … make sure you check to keep transparency (transparent pixels)
@hasbroboy87 … what imageEditing program are you using?
Now, the background that you want transparent should all be highlighted. Just click delete, and it will be transparent. If the instant alpha tool doesn't catch some parts of the background, you can use the rectangular selection or the circular selecting, and then delete the highlighted area.
Hope this helps,
Jack McGraw
I used the Adobe apps for my graphics, but here is a cool link I thought you might be able to use.
http://www.gimp.org/tutorials/
Good Luck,
Kai