Whichever slide objects you place on your PowerPoint slide, their position and alignment matters a lot — be it shapes or even the many inserted pictures. If you see randomly placed pictures on a slide, then you need to explore alignment and distribution options. In some cases, a non-aligned, haphazard arrangement may work — but most of the time you will have to align objects in a proper way on your slide.
Learn to align and distribute pictures in PowerPoint 2010 for Windows.

