Often an image almost perfect for your purposes has an unsuitable background. Here you'll learn an interesting technique applicable to background changes. It can be used to create an aureole, or halo, for any object or person.
For starters, open the image you want to change. I chose an Avril Lavigne theme.
Select the entire background using the Wand tool (W). You can click on any spot of the background and then add unselected parts to it holding down the Shift button.
Go to Quick Mask Mode (Q) and then apply Minimum filter (Filter>Other>Minimum) with a 30-pixel radius.
Apply the Guassian Blur filter with the same radius as in the previous operation (30).
After that apply Crystallize or Mosaic filters setting the size of a cell to 13.
Go back to normal mode (Q) and fill the selection with white or any other color you wish (D, then Ctrl+Backspace).
Have fun experimenting!
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