I'm just a user here, and no expert at all, so I don't know the technical terminologies. Apparently, there are different types of web addressing's and different types of images... and BPL's "a href" is only good for a certain type of address, just like BPL's "src" is only good for "img" type images. I know that I've encountered linking failures with other types of addresses and images before.
As proof, I successfully linked both your photos and Patagonia website at Backpacker Forum!
I know I am not adding anything profoundly useful, but rest assured it's not "you". :)