Any way to restore maps from modules?

I've been playing around with the maps in Lost Mine of Phandelver, and I've run into some challenges -- which hopefully there are ways to address.

For example, I often want to change lighting. However, even with the original layer staying locked, it seems that many (all?) options are still destructive. I've tried the "revert changes" in the Campaign>Images window, but it doesn't actually revert my lighting changes. Is there any reliable way to restore a map to be as it was before I started mucking with it? Barring that, is there a way I can make a copy of a map which I can muck with leaving the original map unchanged? The most damaging thing I've done is accidentally remove the lighting mask, which is not undo-able...

When you edit a module record (in your case an image record) all of that data is stored in memory and written to a local file so that the next time you load your campaign the changes are there. When you revert changes, the data from the local file is deleted - however, it appears that if an image has been opened, it doesn't fully remove the edited data from memory. You should see the base image if you restart FG after you've reverted changes on an image. I know this might not be an option if you're in game, but that appears to be the workaround to get back to the base image after changes have been made. EDIT: or reload just the module as mentioned by Zacchaeus below.

It would seem that if you do remove the existing lights (rather than just add more or edit them) then reverting changes doesn't bring the deleted lights back. However closing the module and re-opening it does (this also resets the lighting mask as well if you delete that). Reverting changes does seem to remove anything else; for example I tested the Line of Sight by removing a bit and adding in a new bit; adding a mask and making holes in it; and changing elements of the grid. All of these were removed and the map went back to it's original state using revert changes.

You can make a copy of any image by dragging the link icon in the image list for the image and drop it back into the image window. (You can do this with anything in any list to make a copy of the item).

Ah! Yep, that works. Thank you both!

And thanks for the tip about how to copy... I was looking for a right click option, menu option, or whatever. I'm still getting used to the interface quirks.