Copy of what I posted on the comments of the site:
Images are working again, sorry for the inconvenience
Yesterday evening I created a separate test site to avoid breaking things on the real site when doing changes... so it had the opposite effect as intended
Actually why images were working for some and not others: I think if you were using
www.imcdb.org images were fine, but if you were using the non-www version you were directed to the test site which does not have access to the image (but the database was still the normal one, so all other content was there).
Now both with or without www should be fine.