dict.leo.org - missing language flag images

[Rava77]

This is what a query on dict.leo.org looks like when using ANM in "Simple CSS" - the default is not working for that site.
As you can see in the screenshot all the small language flag images are missing and are replayed by empty boxes:

Here is what a small part of the above screenshot looks like when using ANM in "Disabled" so that you see what I meant by "flags and empty boxes":

I do not recall this ever happening with any other site. Any suggestions to fix that or is this a ANM V1.0.13 bug?