Sharing to Elgg from mobile

I’ve been trying to figure out how to share easily and elegantly to my Elgg site from mobile. Most of my users are on iPhone, so could Siri Shortcuts be used? Idea is to create a shortcut that selects some photos, adds some text and then posts it. As you can tell, I’m not a developer :|
Shortcuts can launch web pages, access core iOS services and native applications, run scripts to interact with web pages so it seems like it should be possible. Anyone have experience to share?