In Tidypics 1.8.0RC (last "official" release) the river entry created on uploading new images had the tidypics_batch entity as object_entity. I kept this unchanged. The problem was when commenting directly on the activity page such an entry the comments did only show up in the activity river attached to the upload entry but not on the album page or any image within this album.

So, I changed this in the following way already in my forked 1.8 version of Tidypics:

* the original comment (annotation) to the tidypics_batch entity is still created (and will still show up only on the activity page). But there is no new separate river comment entry created.
* in addition there's a second comment annotation created (with the same content) that is attached to the album the tidypics_batch belongs to. This comment will then also show up on the album page. For this comment annotation a new river entry was created (with album as object entity).

I think this way the commenting on Tidypics entities (with the three subtypes album, image and tidypics_batch) the behaviour is more on the line of other plugins with only one subtype (where comments made in the river are also displayed on the full view page of these entities).

What I did not in the Elgg 1.8 tree of my Tidypics fork is updating the already existing tidypic_batch river comments. But I thought the upgrade of an existing site to Elgg 1.9 (which made it necessary to update the river entries for images and albums anyway after the Elgg core upgrade script that converts the comment annotations to entities) would be a good opportunity for upgrading the old river entries of tidypics_batches to match the newly created entries.