Flickr doesn't have such terms with regards to photos (text is a different matter): to quote:
"(b) With respect to Content you elect to post for inclusion in publicly accessible areas of Yahoo! Groups or that consists of photos or other graphics you elect to post to any other publicly accessible area of the Services, you grant Yahoo! a world-wide, royalty free and non-exclusive licence to reproduce, modify, adapt and publish such Content on the Services solely for the purpose of displaying, distributing and promoting the specific Yahoo! Group to which such Content was submitted, or, in the case of photos or graphics, solely for the purpose for which such photo or graphic was submitted to the Services. This licence exists only for as long as you elect to continue to include such Content on the Services and shall be terminated at the time you delete such Content from the Services." from Yahoo ToS.
Imageshack.us is even more clear:
"he content that you distribute through the ImageShack Network is owned by you, and you give ImageShack permission to display and distribute said content exclusively on the ImageShack Network.
You may revoke this permission at any time by requesting your content to be removed. Such requests will be processed within a maximum period of 24 hours (but usually as short as one hour). You may request deletion and/or mark your content private through our sites' user interfaces, or by contacting ImageShack directly. After your request is processed, ImageShack will cease distribution of your content within a maximum period of 24 hours (but usually as short as one hour) and will absolve itself of any ownership of said content, implied or otherwise.
ImageShack will not sell or distribute your content to third parties or affiliates without your permission. Third parties may exercise the following options regarding your content:
Third parties may hyperlink to the page that displays your content on the ImageShack Network without modification and with proper attribution to you.
Third parties may request permission to use your content by contacting you directly.
All requests for permission regarding your content usage directed at ImageShack will be forwarded to you. All uploaded content is copyrighted to its respective owners. ImageShack directs full legal responsibility of said content to their respective owners. All content generated by ImageShack is copyrighted by ImageShack. ImageShack is not responsible for any uploaded content, nor is it in affiliation with any entities that may be represented in the uploaded content"
Twitrpix ToS allow them to do more or less what they want with the content, but only on their site and the agreement terminates as soon as you remove the pic.
So, it seems that only twitpic, twitgoo and posterous are claiming rights to use the photos outside even after one removes it from service. Please check your facts - twitpic is in a minority here and all such services deserve to be ostracized by the users.