If I post a tweet with a link to a picture it will only display the link. But if twitpic post an image link (or rather a link to a page with an image) twitter will render the image (smaller albeit).
I know twitter now has Tweet Entities but those appear to be for reading and not writing.
And yeah I could use twitpic but I rather not since we already have the images saved and ready to go.
Basically how do you become like: twitpic, lockerz, photobucket, yfrog... so on so that twitter recognizes your links as images.
Update: I know twitter will provide upload image api soon but I would rather have the image content on my site.