's tile sets contain six tiles of equal size, lined up
horizontally. From left to right:
Player One's marble as it appears on the game boardPlayer Two's marble as it appears on the game boardThe game board's backgroundThe top row's backgroundPlayer One's marble as it appears on the top rowPlayer Two's marble as it appears on the top rowThis image shows the six tiles in a tile set
Tiles three and four will be repeated over the game board and
top row unless a full window background image is specified in the
theme file.
PNG format is recommended for tile sets. The first, second, fifth
and sixth tiles should contain some transparency if you want the
background to show through. The third and fourth tiles should be
solid, with no transparency, even if you'll be using a full
window background image with your theme.
Tiles can be square or rectangular, and any size you like. Most
of the tile sets that come with  use square tiles measuring
50 pixels by 50 pixels.
For a full window background image, there's a bit more work to do.
Let's say your tiles measure 50 by 50 pixels each. The game's display
measures 7 by 7 tiles, including the top row, so the ideal background
image for your tile set measures 350 by 350 pixels.
will automatically scale the background image if it doesn't
match the tile set. This means you can make "large" and "small"
versions of your theme, both using the same background image,
just by having a large and a small version of your tile set.
So, you now have a tile set and perhaps a background image to
go with it. The next step is to put them in the right place.
