This is just one of over seventy Media Asset Management (MAM) systems covered in the Media Asset Management Guide. Also see descriptions of the workflows.
Alfresco Enterprise Edition seems to be the same product as "Alfresco on-premise."
Also available as part of the "Alfresco One" package along with Alfresco in the cloud. Alfresco One is "...our flagship product for hybrid ECM that includes Alfresco on-premise, Alfresco in the cloud, and a robust content sync that connects the two." This page offers a basic overview of the Alfresco One model.
"Most images can be transformed to most other image types, but you can never transform audio or video files." Consult this list of file type transformations.