Sometimes, I play maps (Like the Strip series or some bounds) that have the map terrain arranged in such a way that it forms an image on the minimap. I asked some other players how one was able to render images on the minimap, since there was no way in hell one could draw terrain by hand so that it looks like porn or any other image (Like that of a Zergling in the "Zergling Run" series) when viewed on the minimap. I was consistently told that some software or certain map editors are used to render an image as StarCraft terrain as best as possible. Does anyone know what software or map editors can be used for such purposes and where I can download them?

You can use MapSketch to do it.