Got a working understanding of STDIO file functions?
How do propose communicating the files and addresses?
The .ELF format is well documented and in use for many decades. You could use this object file format to describe multiple sections, one for each image describing the address and size, and position within the file itself.
Personally I think writing a packaging tool might be simpler than using the linker.
You could create a .S assembler file and use .INCBIN, use the linker and linker script to generate a .ELF
A .HEX might be simpler to pull-off, as you can just dump out each file in a hexadecimal format, with the address attribute you want, and the address space can be sparse.
For a .BIN you have to make a large linear image, big enough to hold all of the files, with the gaps/spacing or address offsets you want. Allocate this large region, chose your pad-fill byte (0xFF or 0x00, or whatever), then enumerate through your file list, offsetting into this buffer, and once done write the whole buffer to a new, singular, .BIN file
