Wait wait wait.... I dunno if you can put autocad and photoshop in the same level? Autocad is for engineering/architechtural designs, photoshop is more so for graphics?
Haha I'm not saying they're the same, just that you need to spend time learning to use either of them. And SmartDraw is used for drawing engineering stuff too.
SmartDraw is great for drawing the kind of stuff that's in the image Sev posted - simple geometrical drawings that you can easily edit and combine with other shapes, inserting outside images into a frame and so on.
Sevastase, check out the link I posted. You'll be able to create all those images within a couple of days with SmartDraw.