For mobile games, we have to be careful with the use of TGA image because of the memory performance. Each case is different. Here I wanted to make a sculpted wall, a real 3D model , instead of putting a tga image of this wall.
1 ) create a plane square
3 ) use bitmapfit on the square (choose your texture 1024×1024)
4 ) Apply your texture from the Material editor
5) Start to make a line to draw the shape of your texture, the borders of the wall
6) place each vertex
7) Convert the line to editable poly
8) extrude volume from the editable poly
11) Import the fbx model and the texture in Unity
12 ) Enjoy !