I moved from Xfce4 to i3 recently but I still use
xfce4-screenshooter. It works properly and I had no problems with it except that I can't save to clipboard.
On this page it is written:
Copy to the clipboard
The Copy to the clipboard option allows you to paste the screenshot in another application, such as a word processor. This option is only available when a clipboard manager is running.
Althrough I didn't have
clipman while I was using Xfce, I was able to use option copy to clipboard. I want to know what program (clipboard manager) should I run at the start of every i3 session.