This is a short, step-to-step tutorial, on how to edit your Gta3.img file using Alci's.
If, You are wanting to install any sort of skin mods, textures, vehicle mods etc. You may download Alci's IMG Editor here.
Using Alci's is not difficult as this tutorial was also made to help you out. First
You will need to download and locate the application.
I downloaded the program and extracted it to a folder I made on my desktop.
Right click the executable and click 'Run as administrator'
When 'Run as administrator' is clicked, you will be prompt to click 'Run'. The program will then start to which you need to click the Open icon.
Clicking the Open icon with cause a dialog box to pop up making you locate and select the gta3.img.
It is usually found in: Computer ► Local Disk (C ► Program Files (x86) ► Rockstar Games ► GTA San Andreas ► models
Clicking the 'Import' icon, locate and select the files that you wish to replace with the files in the gta3.img. When all files are selected, click 'Open'. (Left to Right)
When the files are imported, they will be removed/overwriten if they exist.
(Here, You also have the option to export the original files if you ever want to put them back.)
Finally, You will need to save the image file before re-building it. (Left to Right)
If you have any questions regarding this tutorial, please comment below!