Because they are fake and stock pictures. You will never know who you may get until she show ups at your door step. If you are lucky enough you could get a girl that looks like one of then pictures, more often then not it will be a older cubby Asian girl that show ups.

I have seen 4 different girls from there and pics were always the real girl and a fair representation. They are photoshopped, of course, but that's the norm for most providers.  Personally I think most of the girls look better in person than the photoshopped images.   They might trim off a couple of years but the tradeoff is that they look like they are plastic asian barbies with too much makeup.  Still, it's easy to see that the girls have great bodies and pretty faces and the girl that answers the door is always the one in the pic.