Why have blog posts featured Images with 'non-English' file names recently stopped showing when shared on Facebook? We noticed it about 2 weeks ago. If I change the image file name to English letters, the image shows.

Why have blog posts featured Images with 'non-English' file names recently stopped showing when shared on Facebook? We noticed it about 2 weeks ago. If I change the image file name to English letters, the image shows. Why has this change suddenly occurred with no warning? We have hundreds of shared posts on Facebook, all of which have non-English featured image file names. I have since found out this problem also affects other non-English languages such as Hebrew.