How do I turn binary file data into hex representation

[Nlits]

Example of the first part of my problem:

Expected bytes

> BIMG010a���###$$$%%%"""!!!�

�

What I got from toHex(And back again)

> BIMG010aººº###$$$%%%"""!!!º

ï

It is completely broken. Please help.

Conversion script:
    
    
    proc toHexSeq(str:string): seq[string] =
     var hex = toSeq(str.toHex.items)
     var output: seq[string] = @[]
     for i, x in enumerate(hex):
       if (i mod 2) > 0:
         output.add(hex[i-1] & x)
     return output
    
    Run

Thanks,