Hi Chris,
Both links seem to work fine. One note:
for the photo page, (https://airport-data.com/aircraft/photo/001931031.html in your example), the new site does not use '.html' anymore, now link is https://airport-data.com/aircraft/photo/001931031. But any old link with ".html" will be redirected to the correct url, so this should not be the cause.
After you insert the link, do you see thumbnail? if yes, click the link bring you to which page? could you share a screenshoot?
Ken