It's not possible to compress more than a certain amount. E.g. you can't store every possible combination of 12 bits with only 8 bits. It's trivial to expand 8

It's not possible to compress more than a certain amount. E.g. you can't store every possible combination of 12 bits with only 8 bits. It's trivial to expand 8 bits into 20 bits following some procedure, but it's literally impossible to do the reverse.