digiKam makes it relatively easy to tag photos. Select one or several photos, expand the Caption/Tags right sidebar, tick the tags you want, and press the Apply button. You can also assign keyboard shortcuts to the often-used tags to speed up the tagging process. Continue to read
This is a companion discussion topic for the original entry at https://www.digikam.org/news/2011-05-25_assign_keyboard_shortcuts_to_tags_in_digikam/