- Open Player.img with the ImageTool (File>Open)
- Search for denimsred.txd or any other trouser-txd(Edit>Find)
- replace the TXD-file with the new denimsred.txd (right click>replace)
- close ImageTool and start GTA SA

ingame:
- drive to Sub-Urban and buy the red Jeans or the trouser which you replaced
- enjoy

