Considering the above, do you still want me to write a patch for this?

Some options:

1. Add the above as a remark in the user guide or the wiki.

2. Add a variant of the dvipng backend, say dvipng-xcolor, as explained.

3. Remove the dvipng cli color code and (maybe just deprecate or ignore)
the use-xcolor option altogether and make xcolor the default for every
backend.

4. Do nothing.

What do you think?

Regards
--
Carlos