iOS iPhoto Sharing

I recently purchased the iPhoto app for iOS. I would like to replace the "Photos" app with it, however I've found one annoyance I haven't been able to resolve. The iPhoto app does not allow sharing via messages, only Facebook, Twitter, printing, and the option to send a photo to the camera roll (and a couple more...). Is there any reason for this? Why do I have to send it to the camera roll to share via iMessages or text messages? Thanks for any help.