A while back I inherited a photo solution that had been written some years earlier. Similar background - many images, formally named, hi res, stored on a specific server. In this case, that 'hi res' body also has a 'medium res' and a low res mirror copy on separate servers.
The FMP solution is set up with fields that show each server address (globals). As each record describing the image is entered, the 'formal name' of the image is also constructed. Calc fields then concatenate the server address with the file name, so that the image can be displayed in a calculated container.
Note: two stages to the endeavour - source material is scanned at hi res, then the low res copies created. Images (etc) get a file name assigned at that point, and the (later) FMP record applies the same naming protocol.
It continues to work very smoothly across WAN and LAN, many GBs of data later. 'Old fashioned', but effective and resilient.