perl -MPath::Tiny -MURI::file -e 'my $a = path(".")->visit( sub { $_[0]->is_file and /\.(png|jpg|jpeg|svg)$/i and $_[1]->{$_[0]}++ }, { recurse => 1 } ); system(qw(gsettings set org.gnome.desktop.background picture-uri), URI::file->new(path((keys %$a)[int rand((scalar keys %$a) +1)])->absolute));'