Should Subject Context be automatically copied from source images be default when constructing SRs

[CPBridge]

There is quite some boilerplate required to correctly set up information in the Subject Context when constructing SRs. This information is optional according to the standard but required by some tools, e.g. Slim, and should probably be considered best practice.

Since this information is generally contained within the source image, we should consider copying this information from the source images.