In fact, making a weapon/section/doodad/whatever sprite is very easy. You can do it with any kind of image manipulation tool, from MS paint, to GIMP, and from GIMP to Photoshop.
Essentially, you draw a sprite on a said image manipulation tool, then save it, either as a PNG or GIF (if you want to use it as a doodad, or animated ones). And then, it's done, just import the sprite to the shipmaker by simply dragging it to the section palette or the workspace if you tend to use it as a section; or select the 'Weapon Sprite" when tinkering with a weapon, choose your desired sprite. Now you can have your shiny custom sprites used on your ships.
One important note: Please make sure that you maintain a neat and standardized file structure for your custom sprites, or else things will go so bad that others will find accessing your ships is a pain in the ass, for you had messed up the file structure of your custom sprites. (Which something Arc wanted my head off after running my Corp mission.)
The one who makes
[Claim disputed] mechas with BSF currently. (And the creator of the Sabot Cannon of the BSFCE.)Worlds At War Universe:The Earth CoaltionMars People's UnionThe Free City-states of Luna