Can I share a photo on facebook from an IPhone app and include a "suggested text" (default description).
presentShareDialogWithPhotoParams only has photos to include
presentShareDialogWithLink needs to be an actual link...
(I have a URL of the image on my server, but it is not a nice link)
No, you cannot include any text for the message part of the post. Doing so would be against section 2.3 of the Platform Policy (https://developers.facebook.com/policy/)