You can find this filter in
Filters->Render->Pattern->Jigsaw
Figure 11.209.
Jigsaw filter example
This filter will turn your image into a jigsaw puzzle.
The edges are not anti-aliased, so a little bit of smoothing often
makes them look better (i. e., Gaussian blur with radius 1.0).
Tip
If you want to be able to easily select individual puzzle-piece
areas, as for the example above, render the jigsaw pattern on a
separate layer filled with solid white, and set the layer mode
to Multiply. You can then select puzzle pieces using the magic wand (fuzzy
select) tool on the new jigsaw layer.
13.10.2.
Options
Number of Tiles
How many tiles across the image is, horizontally and
vertically.
Bevel Width
The Bevel width slider controls the slope of the edges of
the puzzle pieces (a hard wooden puzzle would require a low
Bevel width value, and a soft cardboard puzzle would require
a higher value).
Highlight
The Highlight slider controls the strength of the
highlight that will appear on the edges of each piece. You
may compare it to the "glossiness" of the material the
puzzle is made of. Highlight width is relative to the
Bevel width. As a rule of thumb, the more pieces you add
to the puzzle, the lower Bevel and Highlight values you
should use, and vice versa. The default values are
suitable for a 500x500 pixel image.
Jigsaw Style
You can choose between two types of puzzle,
Square then you get pieces made with
straight lines, or Curved then you get
pieces made with curves.
Published under the terms of the GNU General Public License