Not sure if it's just me, but all of the Monster and Magic Items large images for Homebrew and Official content, are showing a broken link.

For example, the Dolgrim (https://www.dndbeyond.com/monsters/487585-dolgrim) has this link to it's image: https://www.dndbeyond.com/avatars/thumbnails/7725/608/1000/1000/637091619688542557.png

It shows as broken and opening the link in a new tab shows:

<Error>
<Code>RequestHeaderSectionTooLarge</Code>
<Message>Your request header section exceeds the maximum allowed size.</Message>
<MaxSizeAllowed>8192</MaxSizeAllowed>
<RequestId>8YV4TDC8QFADSF4W</RequestId>
<HostId>VkZVqPEf3Gbjqrikcb1CyWLAVLqxEM/4cHIzSiiVBIKn4jSaIMyhRpHNYqSupopuPWiLacI4PiM=</HostId>
</Error>

I will note that if you open the ERFTLW book, the statblock image works fine: https://www.dndbeyond.com/avatars/7725/609/637091619689636245.png

And 10 minutes later it appears to be working again.

The "request header too large" issue is related to D&D Beyond's use of tracking cookies and it can happen seemingly randomly whenever you use the site a lot. Clearing cookies and local storage for dndbeyond.com and logging in again usually fixes it for me.