There is only one breed of pit bull, the American pit bull terrier. And you cannot tell whether or not you have one by pictures alone. You would need papers (ie a pedigree) to be able to tell if your dog was an apbt
Now there are several other distinct breeds that are.commonly referred to colloquially as "pit bull", among them the American Staffordshire terrier, Staffordshire bull terrier and American bully. But again, without a documented pedigree there is no way of knowing which of these breeds or mix thereof your dog may be.
That being said, welcome to the forum. There's a ton of info, I suggest you read up and ask questions. We're here to help. As for the pictures, if you've just joined you typically have to wait a bit before it will let you attach, and there's a limit. I would suggest uploading your photos to photobucket and you can then paste the img link into your posts.