Data ~= Files 

A file is nothing but some data with an associated key. What I'm talking about is storing data, with a key so it is easily retrieved. Files are traditionally identified by an extension such as ".jpeg" but this is quite wasteful so I propose replacing it with a number (maybe 3 or 4 byte or a VarInt). So you have:

1. Raw data
2. Key (filename)
3. Data type (1=jpg, 2=png, ...)

FYI, Bitcoin SV is already doing something like this, and they already have a system devised for splitting up large files into several OP_RETURN transactions, but I'm not sure if they have a keying mechanism. That is the icing on the cake.