on
any open image to select an area to use as a pattern. Feather must
be set to 0 pixels. Note that large images may become unwieldy.
Photoshop
comes with a set of Illustrator format files that you can use to
define a preset pattern. Each file in the PostScript Patterns folder
contains a single pattern that you can scale and render at any resolution.
Open the file, select any rendering option, and then define the
pattern.