So it goes like this:

First: You should look for some screenshot tool that let you control it's behavior using command-line.

One good solution can be gnome-screenshot.

Chances are it has already been installed if you are using an Ubuntu-based distribution like Linux Mint. If not, you can install it:

sudo apt install gnome-screenshot

After that, simply add a keybinding to your i3 configuration with your desired options:

bindsym Print exec "gnome-screenshot -ac"

Take a look at man gnome-screeshot for more option.