According to
http://msdn.microsoft.com/en-us/library/ie/ms460194.aspx
:
RegistrationId
Optional Text. Specifies the identifier of the list or item content type that this action is associated with, or the file type or programmatic identifier (ProgID).
RegistrationType
Optional Text. Specifies the registration attachment for a per-item action. Possible values include:
None
List
ContentType
ProgId
FileType
So, you are using List RegistrationType, your RegistrationID should contain the identifier of the list.
And by picture folder, i think you mean picture library, which is a list.
And according to
http://msdn.microsoft.com/en-us/library/cc263911(v=office.12).aspx: feature is scoped to Farm, Web Application, site collection or site. Your picture folder can be on different site.