I'm using the default screenshot application that comes with Ubuntu
When I was using it earlier to take screenshots of the lock screen I had set a long time delay, but forgot to change it back after I'd finished. When I next took a timed screenshot I had to wait a long time for it to take because the delay was still set so long.
Clicking the icon to relaunch the screenshot application has no effect whilst the timer is in effect, I imagine there is probably a simple terminal command to shut down an application, but I don't know it! Is there a way to do this?