Barebones image differs.
Build steps, C version:
$ cc -g -O2 -march=native -pthread idiff.c -o idiff
idiff will use libspng if available (link -lspng),
falling back to libpng if available (link -lpng),
or stb_image from the ext/stb submodule as last resort.
Build steps, Go version:
$ rm idiff.c
$ go build
Usage:
$ idiff <left> <right> [diff.html]
Suggested workflow:
$ <generate known good images in good/>
$ while working ...
$ <generate new images in bad/>
$ idiff good bad && {start,open,xdg-open} diff.html