If you do not want to download just about one gig file, do this so you do not have to face this predicament in the future.
Steps:
1) Right Click on your gta3.img.
2) Click 'Copy' on the small menu that comes up.
3) Right Click anywhere (not on any files or folders) and click 'paste'
4) Go to the refrigerator and grab a soda, walk back to your PC chair and sit down.
5) Be happy that next time you screw your game up, you don't have to download 1 gig of crap again.
On a fairly obvious side note: Always keep a stock Gta3.img.
Currently high-jacking your thread,
- Hayden.