While searching for embedded non-free ICC profiles:
find . -regextype posix-extended -iregex '.*\.(jpg|png)' \
-exec sh -c 'identify -verbose "$0" \
| grep -i copyright && echo "$0"' {} \;
The following files showed up. The proposed alternative files just
remove the embedded possibly non-free and anyway useless ICC profiles:
exiftool -icc_profile"-<=" $files
The images have been checked as identical to their source.