Searching for "highly compressed Wii ROMs" usually refers to finding game files (ISO or WBFS) that have been shrunk to save storage space. While original Wii discs are 4.7GB, many games contain "padding data" (junk files used to fill the disc) that can be removed without affecting gameplay. There are three primary ways Wii games are compressed:
Some popular tools for compressing and decompressing Wii ROMs include: wii rom highly compressed
Here are some best practices to keep in mind: Searching for "highly compressed Wii ROMs" usually refers