I have inserted a file "generic.txd" that contains textures of palm trees and roads, the problem is that the texture of the road is only generated in a single part of the map as you can see below: (https://i.imgur.com/fqVUcay.png) (https://i.imgur.com/JcKJl9a.png)
It's because not all of road textures are used from generic.txd, only a few ones, like those in the screenshot. The rest of road textures are located in gta3.img. If this wasn't the case, generic.txd would be a lot larger than it usually is.