It has been a long time coming. iOS now has inline images.  Like the Mac app, it is running HEAD to see if the link sent over is an image. Improperly configured web servers may not work here. However, this works very nicely with XEP-0363. This is for HTTPS only Monal does not deal with HTTP at all and will pass anything with out SSL over to safari.  This is available in the beta that is going out right now.  Along with inline viewing, there is a nice photo browser you can use to pass the image off to other Apps.