Open in a new window the picture of a pepper: File ? Open (ctrl+o).

Pepper Wallpaper

Mark it out along its contours, choosing previously the Polygonal Lasso Tool.

Pepper Wallpaper

Make a copy of it: Edit ? Copy (ctrl+c) and get back to the wallpapers window to insert the pepper on a new layer: Edit ? Paste (ctrl+v). Make the corrections on its size, applying the next selection:
   
Edit ? Free Transform
(ctrl+t).

Pepper Wallpaper

We'll make the corrections on its brightness and contrast also, using the here shown option: Image ? Adjustments ? Levels (ctrl+l).

Pepper Wallpaper

Mark out now a part of the pepper by using the Pen Tool and Make Selection command.

Pepper Wallpaper