http://www.peacekeeper.com/3dgs/gsjanfx.html

// draw any size (should be smaller than entity) BMAP onto entity
// 0,0,0 is transparent
dllfunction FXImageListDrawXY(string, entity, x, y);

I would say a 1024x1024 texture for the golf ball and then FXImageListDrawXY() your 256x256 texture in the center.