Please know that I am not endorsing any one brand of diaper over another; I used what I had on hand to model the different types of diapers for you. There are many many brands of diapers available other than the ones shown here. These photos are just to give you a general idea of what the different types of diapers look like. I have added a brief paragraph covering some of the advantages/disadvantages of each type of diaper- these are very general and may vary with different brands. Please email me if you'd like to see more info covered here or have any suggestions! Thanks!
Above is a flat diaper. It is made of one layer of fabric, and can be folded in many different ways to create thickness for absorbency where needed. Use with a cover. Advantages: good for custom folding, wash well, and dry very quickly. Disadvantages: not as absorbent as some other cloth diapers, and it may be hard to find good quality flat diapers (I don't know- these were handed down to me).
Above is a 4x8x4 (4 layers of fabric on each side, and 8 layers of fabric down the center) prefold diaper. It's called a "prefold" because the layers of thickness are already prefolded for you. (You still need to fold it onto the baby!). Use with a cover. Advantages: not as much folding involved as with the flat diaper, but you can still custom fold the diaper to fit your particular baby. Washes well and dries fairly quickly. Disadvantages: The many different types of prefolds out there differ in quality and absorbency. It can be hard to tell the difference at first. In general, if you want an absorbent prefold, find a Diaper Service Quality (DSQ)prefold with 4x8x4 layers. 4x6x4's aren't quite as absorbent, but also aren't as bulky. (They work fine on my 8 month old who isn't a heavy wetter.) The best quality prefolds are usually found through mail or internet order. The diapers usually found in department stores, while they have their place, are generally not as absorbent and have a reputation for leaking. Try to get samples of each and see what works best for you.
Above is a fitted diaper. It does not need folding like the flat or prefold diapers. Use with a cover. Advantages: fitted diapers generally have elastic around the legs, helping to keep leaks in the diaper and away from the cover. Easy to use and require no folding. Disadvantages: not always as easy to custom fit as a flat or prefold diaper. Many brands of fitted diapers take a long time to dry. Not every cover will fit over every fitted diaper. You may need to do some research to find the perfect covers for your fitted diapers. Fitted diapers can also be expensive.