If you really only want to pack multiple files into a container, why not do it yourself? It's quite simple to do (an index with offsets to the files and sizes and the data itself). You can even apply compression before you save and decompression before you load.
Could you show a code sample or link me to a resource. It'd be very helpful
That is actually something that would be a good exercise in a 1st year course in programming. Hell, if I teach again, I'll probably do it.
open file
read in "header bytes" as you've defined them
read in the number of bytes required for each file and store them as appropriate in variable
close file
do what you want with the data
Similarly for saving.
If you don't know how to do any one of those operations in your language of choice, then, in all seriousness, you need to buy a book, or take a class.
For books, I would recommend any of the O'Reilly Learning series for what ever programming language you are programming (should it exist), or the Dietel & Dietel How to Program series. The selection of the D&D books is extensive. So, I'd be surprised if they don't have the language that you're looking for.
When it comes to courses, for practical programming, you'd be better off finding a technical college than a University. Any intro course should do… should.