Yes, you can. There are two ways- One, use a Screenshot GUI app that allows you to set the file type when you save it- gnome-screenshot or xfce4-screenshooter will do it.
The other is to change the filetype in the .xml configuration file, but I suspect you may want to try another avenue, first.
Which Desktop Environment are you using (or put another way, are you using Zorin Core, or Ultimate or Lite?)
You can only run one ROOT installation at a time. If you are running Synaptic (Or Synaptic is open), then dpkg cannot get a lock in terminal because Synaptic has the lock. If you are running an installation in terminal, Synaptic will not be able to get a lock, for example. Whenever you see the error that it could not get a lock- Just finish the other installation, first.
I think this issue needs a new thread. But I agree with Carmar in the other thread- I would encourage you to reinstall, choose Zorin Lite and set it up with nomodeset and then we can Update your drivers.
I started out on Zorin Core (which uses Gnome Desktop environment) and it was nothing else except a lesson in frustration.
Gnome is not user friendly, they have removed or hidden a lot of features and to anyone moving to Linux, Gnome aggravates more than it helps.
XFCE Desktop is Much more user friendly. Settings are generally easy to find and are highly configurable. The problem solving and troubleshooting is usually easier, too.
I have never had Printer Connection troubles on XFCE, I always did on Gnome.
Gnomes File manager is clunky, hard to configure, hard to find the settings, right click offers fewer options...
Zorin Lite is Just Plain Better for someone starting out.
That said, the "lite" seems a bit misleading. it is not lacking in anyway, it is just not Resource Heavy like Gnome is.
Synaptic is a very useful and powerful Installation tool. But it also can only find and show what is in the Repository you have. I gave a link with Apache Open Office Installation instructions above.
Apache Does Not Offer a Repository... (cough)
https://www.openoffice.org/download/common/instructions.html#linux-preinstall
https://www.openoffice.org/download/common/instructions.html#linux-deb