This method gives you total control over quality vs. size.

: Use Dolphin Tool or Wii Backup Manager to compress your own ISO files safely.

When downloading from the web, the game is often packed into a 7-Zip or WinRAR archive, which can sometimes bring the download size down to under 3.5GB depending on the compression level used. How to Compress the File Yourself

This is the dark side of the search. To achieve sub-1GB sizes, hackers must rip out assets. This includes:

Standard Wii game files, often found in ISO format, are typically . This is because the original discs were burned to a specific size regardless of how much data the game actually used.