. This feature, introduced in more recent game updates, completely breaks the rendering of most custom skins. Go into your Graphics Settings Dynamic Character Resolution.
: If the model looks "stretched" or moves unnaturally, the bone weights may be misaligned. You will need 3ds Max or Blender with the DragonFF or Kam's Scripts plugins to re-rig the character to the GTA SA skeleton.
If you have tried everything above and still get crashes:
: Right-click your gta_sa.exe or launcher and select Run as Administrator to ensure the game has the necessary permissions to load external mod files.