I use twitter4j library for tweets, but I cannot handle how to upload an image without any other services like TwitPic, yFrog etc.
Does twitter4j support this, or do I need to use other services?
You need to change twitter4j code a bit.
There is an explanation here: http://sholtz9421.wordpress.com/2011/10/29/using-update_with_media-with-twitter4j/