There's something wrong in fetching thumbnails for old-lemmy.
old-lemmy.fmhy.net
: https://i.imgur.com/t8OPh7e.pngold.lemmy.zip
: https://i.imgur.com/vuSwxiD.png
Ah, I just noticed this issue isn't restricted to mlmym frontend... So it's something affecting Lemmy FMHY instance as a whole.
Example: