Artists use this thread to suggest a building graphic AND its details. To make graphics, use an application called Inkscape:
( inkscape.org/en/ ). Inkscape is free and creates Scalable Vector Graphics (.svg) files. Building graphics must follow specific tile-size dimensions, particularly at the base of the graphic. The height can basically be whatever, but the width is important.
Artwork cannot contain any copyrighted materials. This includes business logos or really anything that you do not create yourself.
If you submit something you agree that you are giving @Bastecklein the rights to the graphic and that I have permission to put it into the game. Bast doesn't want to turn around and be sued because you submitted a building graphic and then changed your mind. There is no guarantee that Bast will use your artwork, but obviously a building suggestion with graphics already created will greatly increase its chance of being added to the game.
If you submit something you can choose how you want to be credited within the game (optional, you don't have to be credited at all if you prefer). This is an easy and faster way to get more content added into the game.
Keep in mind that Bast doesn't have time to offer technical support or instructions on how to use Inkscape, so if you can't figure it out, you might be out of luck.
The base size for a 1x1 tile is 64x32. Graphics must be some multiple of that. Graphics should also be somewhat in the same style as the rest of the game, so that they fit in with everything.
The above guidelines are for the Human colony.
Zolarg graphics were not made using Inkscape, but Gimp (another free program), but the same size specifications exist.
Template 1x1: forum.ape-apps.com/attachment.php?aid=372
Template 2x2: forum.ape-apps.com/attachment.php?aid=373
Template 3x3: forum.ape-apps.com/attachment.php?aid=374
Capitol 2: forum.ape-apps.com/attachment.php?aid=376