What Files supports my Garmin Device and which Files I should update?

Nuvi 265 is a very old Device. It doesn't manage folder \Map.
This serie of Devices (2xx, 3xx, 6xx, 7xx, 465T, and some others) manage:

• Up to 4 Maps in internal \Garmin folder (gmapsupp.img, gmapprom.img, gmapprom1.img, gmapoem.img)
• 1 Map in \Garmin folder on external microSD (gmapsupp.img)
• some Devices accepts a second Map in \Garmin folder on external microSD (gmapsup1.img)
  
  • nuvis serie 2x0 (Firmware 5.10)
  • nuvis serie 2xxW (Firmware 4.10)
  • nuvis serie 2x5 (Firmware 7.60)
  • nuvis serie 7x5 (Firmware 4.40)
  • nuvi 465T (Firmware 3.70)

As a general rule, folder \Map exists is Devices having folder \.System as well