This is what a cat's page looks like (click to enlarge picture). Some cats have pictures while others do not. This is because only Star (upgraded) accounts can generate pictures for their cats, so if you buy from a Star player, you may end up with a cat that has a picture! Pictures are purely cosmetic and have no effect on the cat itself, its traits, show performance or genetics.
Pay particular attention to the cat's mood: you don't want a moody cat if you're just starting out. A value of 50 means the cat is perfectly friendly, and the more this number goes away from 50, the worse its mood is (aggressive or shy). To keep a cat from getting moody, or to help the cat's mood to move back towards 50, feed and vet your cats to keep the hunger and health as high as possible.
If you want to breed the cat (which you probably do), make sure to look at its age, as well. The last time a cat can be bred is 80 months. If it's a female, check if she has had a litter recently; in this case, you have to add the waiting days in between litters to the age in order to find out whether you can still breed her.
And, of course, a neutered cat can't be bred. They can still be entered in shows, though, and some people buy or sell them for that purpose only.
The expert's opinion will show you how well your cat conforms to the breed's standard, which is important if you want to enter shows. Mixed breeds never have expert reports as they don't have a standard to be compared to and can't be entered in shows.