Simple desktop file that adds checking md5sum to Dolphin via right clicking on any iso file. To enable this function for all users, copy file to /usr/share/kde4/services/ServiceMenus/. For single user only access ~/.kde/share/kde4/services/ServiceMenus/ (your distro may use a slightly different location). In either case make sure it's executable.
If you prefer to have the function available for all filetypes rather than just iso's - simply change the line
If you prefer Clipboard rather than Notifier, install xsel and change the Exec line to:
Exec=md5sum %F | xsel -b
REQUIRES: libnotify-bin, xsel