How much memory does the code the blog poster described leak? How does it respond to edge cases and invalid input? Finally, is it portable beyond one specific OS? Beyond POSIX or Windows-based systems?
The only dependencies are the C standard libraries (this is even mentioned in the blog post). So unless there's some terrible hackery going on (and skimming the source files, it doesn't look like there is), these are going to be more portable than most of the mega-libs you'd be choosing instead.
Mine or stb_*? I know stb_image is quite careful not to leak. It may not handle all perverse input files gracefully though.
As for twok, I believe the error handling to be decent and I don't believe it leaks. I'd be happy to hear of any errors you find. It's only portable to Windows, OS X, and Linux because that's all I have access to. It may work on BSD also.
Right! Coming up with standalone C means coming up with your own versions of hard-to-write simple "system calls" like memove.
I debugged a memcopy (taken from Linux! 10 years ago) on a RISC processor - it had 12 bugs in a dozen lines of code. Not designed to run on RISC but shows how hard it can be to get this stuff right.
Those questions are especially pertinent in C.