Flexibility is a key capability to allow future 5G networks to support varying service offerings over a common infrastructure. 5G-PICTURE investigates the design of programmable compute and transport network infrastructures, able to instantiate third-party 5G connectivity services on demand. This paper introduces the 5G-PICTURE vision on an integrated compute, RAN and transport architecture, and describes a set of innovative functions in the RAN, Transport and Synchronization domains that 5G-PICTURE has developed to fulfill its vision. Initial evaluation results are presented for the aforementioned functions.