A site Firefox has classified as Not Secure and is limiting my abilities to save images from is interrupting my work.

I have been using the site codeskulptor.org for years. Creating images and saving them easily. Lately I have been getting a little shield with a red cross thru it up in the front of the url bar for the page images i wish to save but am not able to as easily as before. I would like Mozilla to approve the pages i spin off as images in new tabs from codeskulptor.org. Thank you, Ben Winsor