[SOLVED] moving files

I am new to Zorin os 7, and I managed to download some wallpapers. I want to put these wallpapers into the same folder that contains the wallpapers that come with Zorin. When I selected the wallpapers and chose Move to and than select the folder for the destination, I get a message that permission is denied. The destination is /usr/share/backgrounds, when I click on properties the permissions for the directory are:
Owner - root
access - create and delete files
Group - root
access - access files
Others -
access files
and at the bottom it shows - You are not the owner, so you cannot change these permissions.
What do I have to do to copy the files to this folder?
Sorry for not posting a screenshot, I have not worked out how to do that yet.
I tried cutting and then pasting but that did work as I was not giving the option to paste at the destination folder.
I tried to use the terminal to move the files but I was having some problems using the cd command until I realised that the names of the folders is case sensitive. But somehow I do not think using the move (mv) command will work because of the permissions of the destination folder.
Any help would be greatly appreciated, thanks.

Thanks swarfendor437, I tried selecting the code but it does not give me the option to paste it into the terminal so I typed it in. The gksudo nautilus command gives the following message. ** (nautilus:14843): WARNING **: can't load fallback CSS resource: Failed to import: The resource at '/org/gnome/adwaita/gtk-fallback.css' does not exist.
I have no idea what this means.
The alternative method did work after I typed it in, and now all my wallpaper/backgrounds are in the one folder.
I understand that ownership of the folder is only temporary, but is there a way to take permanent ownership of a folder that I may want to edit regularly?
I am very new to Zorin and can understand some of the commands as I printed out a list of the more common ones. I am still trying to work out what some things are like Nautilus and what they are used for, but as I have only been using Zorin for a week i expect thinks will become a bit clearer as I spend more time with it. Might be time to buy a linux for Dummies book.
Thanks for you help.

Hi. thanks for those links swarfendor437, I have saved them as PDFs and will have a good read of them over the coming days.
I solved the problem with Nautilus by removing it and then reinstalling it. I realise that I have got a lot to learn, but I have got plenty of time now that I have retired and I am quite enjoying the experience.
Thanks for everything.