I installed dconf-editor. And set the default folder.
When I use hotkeys it still saves in Pictures. But when I use Alt+F2 and type gnome-screenshot it saves in Desktop.
How to make Ubuntu to save in Desktop with hotkeys?
@tateomuro, may be you missed the prompt that told you that this site is not intended to act as a support site?
https://bugs.launchpad.net/ubuntu/+source/gnome-screenshot/+bug/1742443 is probably relevant to the issue that caused you to post here.
For further help, please refer to Finding Help as there are more appropriate sites available to help users of Ubuntu. Good luck.