Facebook doesn’t “officially“ support emailing photos from a cell phone. They only officially support MMS messages, which the iPhone doesn’t currently support. Arggh.
However, despite what’s “official“, the Facebook mobile application still works when you email a photo to [email protected] from your iPhone. In order to get this work, you do have to enable your iPhone on Facebook and enter the confirmation code sent to your phone. Then, the feature may or may not work for you.
It worked fine for me when I first enabled my iPhone about a month ago but then it stopped working after the recent iPhone software update. The problem: if you haven’t added the email address your iPhone is configured to send through to your Facebook profile, it just swallows the incoming emails (with no apparent error or warning). However, once you add the iPhone email address to your profile, it should start working again, at least it did for me.