While I know Volo's Guide is one of the books that is not really being offered because it's now Legacy - I still have access to it (and use it) during my campaign.

I noticed that the Darkling image is missing?

https://www.dndbeyond.com/sources/vgtm/bestiary#MonstersBD

I am at work (shhhhhh!) - so I can't confirm that there is an image in the book. But I am pretty sure there's an image of two Darklings next to each other?

Same image found in this article: https://www.dndbeyond.com/posts/1022-feywild-101-read-about-key-npcs-in-the-plane-of

This image:

Would be nice to get it into the book so I can use it as a reference to my players.

There are suddenly a bunch of broken images on the site. As just one other example:

Go into the character builder, select Create a New Character. On the Race selection, select Half-Elf. There are 7 subraces under that heading (assuming you own all the relevant content). Each of the subraces has its own thumbnail image - and two of the seven thumbnail images (Drow Half-Elf and Wood Half-Elf) are broken.

As far as I know these images were not broken as of a week or two ago.

If you need a workaround, see if this works for you: https://www.dndbeyond.com/monsters/2557737-darkling

Quote from WynnThornton >>

There are suddenly a bunch of broken images on the site. As just one other example:

Go into the character builder, select Create a New Character. On the Race selection, select Half-Elf. There are 7 subraces under that heading (assuming you own all the relevant content). Each of the subraces has its own thumbnail image - and two of the seven thumbnail images (Drow Half-Elf and Wood Half-Elf) are broken.

As far as I know these images were not broken as of a week or two ago.

 
So I've seen where random images appear as broken images. Almost always it's a cache issue. Clearing the browser cache will usually fix that.