When I use the print screen key - PrtSc - I get the option of where to save. That works fine.
However when I shift-ctrl-PrtSc I hear the picture being 'taken' but I don't get a chance to specify the location.
I have checked the following locations and they do NOT have the screenshot:
My Desktop
My Documents
My home directory
As I know holding Ctrl copies the screenshot to the clipboard and you need to paste it in an application to save it.
You can check the shortcut keys in Keyboard Settings.
I played around some more and found that using Alt-Fn-PrtScn will copy the window only and then give me the option of where to save.
2014 - Update
PrtScn - Capture the entire screen (all windows) and ask where to save
Alt PrtScn - Capture the currently focused window and ask where to save
Shift PrtScn - Select specific area for capture and ask where to save
Shift+PrtScn is a better way, as you will be prompted for where to save the screenshot (and by what filename).
Very simple answer to your direct question(s):
Ctrl-PrtSc will copy the whole screen to the clipboard. It is not saved on disk.
To get a partial, you add Shift, whether you use Ctrl (clipboard) or not (save and/or clipboard).
Of course, you probably know that just pressing PrtSc will capture the whole screen and give you the options to save to clipboard and/or save it to disk, with a default directory of ~/Pictures
try using Shutter instead, It's awesome:
However I think you can also try this not sure if it will fix that exactly:
you can also use get to see where it is suppose to be saving them:
Source: Why doesn't the PrintScreen dialog show up in Gnome?