When running a little test notebook with ArcGIS 3.0.3, I am able to display images without issue.

After updating the software to ArcGIS Pro 3.1.0 and running the exact same notebook, I get the following result:

Here are some other examples of failure to display content in an ArcGIS 3.1 notebook:

What could be causing this issue? Again, ArcGIS Pro 3.0.3 works perfectly fine, and updating to 3.1 breaks it.