License problems with "lenna" image set (reopened #253)

[ametzler]

Hello this is a copy of #253 which was erroneously closed.

Quote danstender

Unfortunately, the "lenna" image set became recognized as being problematic for distributing in a free software context [1]. I know this is the standard example image set of image processing for a long time (the model Lena Söderberg was invited to image processing developer's conferences to meet etc.), however we would have to strip out the images out of the upstream tarball due to the licensing issue. From our view, if these example and tests images could be replaced by upstream this would the best solution. But I know that this is going to be an extensive task regarding the Vigra tests, so just let me point to that issue.
[1] https://salsa.debian.org/lintian/lintian/-/blob/master/tags/l/license-problem-non-free-img-lenna.tag?ref_type=heads

At least Debian and Fedora are working around this with with local patches:
Fedora https://src.fedoraproject.org/rpms/vigra.git quoting the spec file

 The "Lenna" files are non-free, we need to remove them from the source tarball.

# wget https://github.com/ukoethe/vigra/releases/download/Version-1-11-1/vigra-1.11.1-src.tar.gz
# tar xf vigra-1.11.1-src.tar.gz
# find vigra-1.11.1/ -name "lenna*" -delete
# tar zcf vigra-1.11.1-src-clean.tar.gz vigra-1.11.1/

Debian https://salsa.debian.org/science-team/libvigraimpex quoting debian/copyright

Files-Excluded: 
[...]
                src/images/lenna_color.gif
                src/images/lenna_color_small.gif
                src/images/lenna_composite_color.gif
                src/images/lenna_gray.gif

[hmaarrfk]

PRs welcome to replace this image with an adequate proposal.

If they are used in tests, the tests would have to be updated.