I'm not sure if this is the right place to post this, but here goes.
So, a couple months ago, I joined a video contest in which I used an image from Wikimedia commons. At the time it was listed as Public Domain as the photographer(s) had died before 1942.
Now, the contest holders are making me check and submit every image/file I used for the video, as to check its copyright status and such. I go back to the page, and lo and behold, it's been deleted. Further searching of the chat log shows that the original uploader had been misinformed and the images were not, indeed, public domain. it was removed shortly after I used it in my project.
Now what can I do? I need to submit the sources within 2 weeks. What are my options? There is a similar image, a painting of said image done for a postage stamp, which is public domain. Is there anything I can do with it?
Thank you for reading, I hope this can work out!