Similar forgetful sharing sites:
https://onetimesecret.com/ – also sends messages. Does not support images or view limits greater than 1, but does support requiring a password to view.
http://volafile.io/ – for sharing files. Create a private or public chatroom where you can upload files and they are deleted after 24 hours. See, for example, the Hacker News room: http://volafile.io/r/BCcsa6.