Detecting original vs. edited (reposted / recompressed) image
My question is if there is a better way to represent ordering in this case other than labeling pairs 0 and 1.

I solved this by creating an artificial comparator layer, which takes two inputs, and outputs 0 if the first is smaller or 1 if the first is greater. This allows backpropagation to correctly push the two away from each other within the same batch.

Also, if there are other obvious improvements in the whole process.

See my other question: Producing a confidence output to use in a weighted average layer