It wouldn't be so bad if not for the fact that the game data itself is often times only a fraction of the actual disc size - for instance, the Super Mario 25th Anniversary Wii disc itself is a 4.7GB, when really the actual game data is only a single SNES ROM (12 MB of useful data, to be precise) and nothing else. However, with disc sizes ranging from 700 MB (CD), 1.4 GB (GC Mini-DVD), 4.7 GB (single-layered DVD), and 25 GB (Blu-Ray), they can get pretty taxing for storage, especially when newer generations of consoles games are getting bigger in file sizes. Disc images (commonly known as ISOs, but ISO is actually a specific format) are faithful software recreations of game discs (when made correctly).
