In searching for a plugin to show thumbnails in the Pose Library, I came across and installed JAsperges’ “Pose_Thumbnails”: You can find the addon on Github
It appears to have installed correctly in Blender 2.78a and I get a nice PoseLib properties window with a search box.
My problem is the box remains black, despite the fact I have poses in my library and created some after I installed the plugin. I press the button to show all poses, not only ones with thumbnails, because I’ve yet to figure out how to create a thumbnail.
The documentation seems straightforward, basically says, “Just start using it.”
So, I wonder if this plugin doesn’t work in 2.78a, or if I’m just not understanding how it’s supposed to work.
As sometimes happens, I tripped over the answer when I was working on something else. With this add-on, you can only add thumbnails in the armature properties panel. The panel that appears in the pose properties panel is only for viewing poses and it will only work after you have made your first thumbnail. Once I made my first thumbnail, I was able to see all poses in both panels. Neat little tool.
You will! It has not been updated to 2.8 compliance and the GiHub has been archived, so I guess it will not be done. Someone could fork the repo and make it 2.8 compliant though…