GTA3.img is the file that contains all the DFF and TXD
file.DFF files are used to decide the dimensions of the object while .TXD files
are the texture files of the object.There are also player.img file that
contains the DFF and TXD files of the player’s object.
Player.img file is use to load the clothes and body parts of
the player(CJ).
You can use the either IMGmanager
or IMGtool to open .img files.
You can find gta3.img and player.img files in the C:\Program
Files\Rockstar\GTA San Andreas\models