Generally you simply sell the unbirthed box - look at my MP store, and look around the Secondary Shops:
http://kittycats.biz/forum/showthread.ph...=secondary
Be aware that selling breedables on the MP takes some work and isn't well supported. And - yes - it only works for Boxes and Perma-Pets (a topic for another day).
If you want to unpack a box for pics, you can get a free repacker at the KC store, but it only works if the kitten is still 0 days old. They are on a table with other freebies that you might want to check out. Go in the front door, turn to the right and look on the backside of the front wall. The Break Free bottle allows you to change your mind regarding partnering two cats, but it also must be done within the first 24 hours.
Collection kitties have special boxes rather than the cardboard boxes, but they also ALL have an image mode, which shows the pic of the kitten inside. Right click and choose "Box" or "Image" on the blue menu.
The kittens purchased from the KC store come in extra packaging with food and vitamins inside that are non-transferable. That has to be opened first to get to the actual boxed kitten. Also, free free cats, and maybe the regular starters (I've never bought them), are generally non-transferable. The Collection Cat boxes are transferable once they've been taken out of the exterior package, but again the food, etc. is not. Look at the box in your inventory if you are not sure.
FYI - the Kitty Cats Addicts group IMs are also a great for learning and getting answers about how everything works, and they're generally faster than the forum. There are usually KC Customer Service Reps on call there as well as in the store, and everyone is so amazing.
(I was answering at the same time Tad was, but pretty much echo what he said.)