Hi Bigcat1967, I don't think you can directly upload pictures to Twitter, meme.yahoo.com is very similar to Twitter and you can upload pictures and videos there, sometimes I make a post in Twitter and continue it in my meme.yahoo.com site George
Use tinypic , flickr or twitpic.com and then tweet it .but in my opinion apart all from twitpic is really best for twitter.
You can only submit one profile picture on the Twitter account. But more pictures on the Twitter used different twitter applications.
First of all your can upload your profile pic but nothing else, you can share pictures as links but apart from that no it's not like Facebook
http://www.twitpic.com is the standard for putting pictures into your tweets. Many Twitter applications like tweetdeck or tweetie have built in support for twitpic.