Google on Sunday started detecting TwitPic.com as a threat. Currently, if you try to access the site from Google.com using any browser (link), you’ll get a malware warning.
Furthermore, whenever you use Google Chrome, TwitPic.com pages as well as Twitter pages that rely on the service will issue a blocking prompt as well.
Now Google has removed the block and access should be restored.
https://twitter.com/twitpic/status/285553241968750592