[Q] Custom PNG Data Chunks

No, PNG says that some chunks should be preserved, if they are marked to be preserved.

However, we have found that most chunks are mismarked for preservation, or not marked for preservation at all (when they should be). Plus, some applications will have problems with chunks that were preserved (because they were marked to be preserved) and really should not have been preserved.

So, to prevent problems with other applications, Photoshop does not preserve unknown chunks.

So, I assume there are no plans to have Photoshop honor the PNG spec with respect to chunks marked for preservation.

Not unless several other apps get their act together...