It's considered "rebuilt" a pic not "falsified", but  directley "re-drawned". This intervention is  necessary when the pic is worn-out/stained/scratched/teared. It's obvious that are mainly old pics to need this threatment. Even in some recent photo, however, it's sometimes necessary a 'reconstruction': in instance in case in which one or more (unwanted) elements are in front of the main subject.
Unuseful to say that's a slow process, requiring high precision. The operators' skill is an indispensable requirement . By our side, we take every due care, to make impossible to discover which is the 'rebuilt' area. We sample the real colours present in the pic, paying attention even to lights and shadows. If the observer hasn't the original pic as a term of comparison, it's impossible to say that the pic has been rebuilt.
Our best reconstructions (for the ANCIENT section) mostly belong to no more living people. We want to keep 'intimate' their relatives' memory.
The two following icons represent the two (ancient & modern) sections. In the examples you'll find specified if it's considered a 'recostruction' or just a cleaning.