Thank you, Steven!! I changed the opacity in the offending section of the js and the images now show up in firefox. Success!
One knock-on effect: changing the opacity seems to have broken the hover transform animation on two of my images (quick links & things to share). Both have the same data-ix=”tile-3″. I tried to change the data-ix to a working one (“tile-2”). I also tried to create two new data-ix groups (“tile-5”, “tile-6”). Neither of these solutions fixed the animation problem — in fact, both broke the images completely.
I guess, worst-case scenario, I can get rid of my hover animations but, they are a nice feature on the site and I’d like to keep them, if possible. Any thoughts on how to fix the new hover transform issue?