The new and improved <sic> way of taking snapshots during a video call is to click on the + on the toolbar at the bottom of the Skype window. That brings a menu where Take snapshot is a choice.
Heh. You won't get any argument from me on that change not being an improvement.
If you're so inclined, you can add your thoughts to this thread on the Skype developer's forum: https://jira.skype.com/browse/SCW-3248