Hi Ross,
Apologies for snapping at you the other day.. I was a bit frazzled with frustration.
Thank you for your detailed reply which has given me further insights and I’ve learned a few new details about the underbelly of OH too.. 
As it turns out Oliver2 helped me out in my original posting article and the solution is there now. He actually ‘re-enacted’ the exact thing I was trying to do and diagnosed the problem. We did try your suggestion about API assigning a url to a string and using the string item as the target item of the image item but it didn’t work. The overriding problem was that the image item seemed to remain empty (even though we could see the meteogram) and thus UI Card saw an empty item and went looking for an image in the Photos directory (folder in Mac speak). That was why i was getting this bizarre url ending of ‘Photos’ in the address bar.
Anyway, you’ll see (if you’re curious) what exactly we did because I put screen shots in the solution discussion. The solution process and exchanges are all there.
Let me know if it makes sense to you and if you found it interesting too.
Thanks again and sorry for being a bit sharp the other day. 
Original post: OH3 url Image won't display
