As far as I understand that iOS app requires also a plugin of the same name. If you got trouble with it you need to ask its developer. Not sure if he reads here regulary. Here is the GitHub repository for the plugin: https://github.com/djmonta/zenphoto-iOS-plugin
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Followed instructions here: http://zenphoto-app.tumblr.com/
https://itunes.apple.com/us/app/zenphoto/id968674016?mt=8