Except in that case you're converting to and from an uncompressed buffer... that...

rwmj · 2024-04-22T14:03:47 1713794627

It's much more useful to have a real file format.

For example, you can generate images from your own code by doing this (with a bit more shell quoting and error checking in the real code):

  fp = popen ("ppmtojpeg > output.jpg", "w");
  fprintf (fp, "P3 1024 1024 255\n");
  for (y = 0; y < 1024; ++y)
    for (x = 0; x < 1024; ++x)
      fprintf (fp, "%d %d %d\n", 255*r[y][x], 255*g[y][x], 255*b[y][x]);
  fclose (fp);

frutiger · 2024-04-22T17:44:42 1713807882

This is the first time I have seen anyone popen’ing a pipeline like that, and writing to its stdin.

Bravo.