Certain images simply do not render and the site displays a HTTP400, as a result the page just shows the ALT text.
For example the portrait picture of the Scarecrow on this page: https://www.dndbeyond.com/monsters/17200-scarecrow

This image has the URL: https://www.dndbeyond.com/avatars/thumbnails/30835/821/1000/1000/638063922184805878.png
Accessing this URL in Chrome & Postman works.
In Chrome it returns a 400 and an XML error message:

<Error>
<Code>RequestHeaderSectionTooLarge</Code>
<Message>Your request header section exceeds the maximum allowed size.</Message>
<MaxSizeAllowed>8192</MaxSizeAllowed>
<RequestId>8962RTKMPVTTXREV</RequestId>
<HostId>7Q43MUlVnEjJpJ96Bq90jN/kvogLAevnU5pZFfgkSKvunlozNipPWPEoQI7SFF4f6lVEtsKsc1U=</HostId>
</Error>

All cookies deleted
Entire cache removed and chrome reinstalled.
Error has been present since December 2025.

An alternate error image is this : https://www.dndbeyond.com/avatars/54366/134/1581111423-160019172.jpeg?width=150&height=150&fit=crop&quality=95&auto=webp 
Which gives the same error.

This is an error that has happened to others: https://www.dndbeyond.com/forums/d-d-beyond-general/bugs-support/156019-images-failing-to-load-on-website?srsltid=AfmBOooZy7NhaQDJt9f-xWPXFW7Nx2R6GsTNnrnU5SxTX-FXYF9FSaZP

This error can be reproduced in post man by adding these headers:
Accept:text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7
Accept-Encoding:gzip, deflate, br, zstd
Accept-Language:en-GB,en-US;q=0.9,en;q=0.8
//Cache-Control:max-age=0
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User-Agent:Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/144.0.0.0 Safari/537.36
Upgrade-Insecure-Requests:1
priority:u=0, i
sec-ch-ua:"Not(A:Brand";v="8", "Chromium";v="144", "Google Chrome";v="144"
sec-ch-ua-mobile:?0
sec-ch-ua-platform:"Windows"
sec-fetch-dest:document
sec-fetch-mode:navigate
sec-fetch-site:none
sec-fetch-user:?1

After spending some time attempting to diagnose this issues I found that ddb had stored 70 cookies on my PC when using Chrome.
I compared to the number when using a cleaned version of Edge - there were only 46 cookies sent by Edge.
Using a cookie cleaner and logging back into ddb I found that all the images appear.

Now when I count the cookies there are only 43 cookies  in Chrome and it now works fine.

I can only conclude that the ddb server which is serves https://www.dndbeyond.com/avatars does not like the extra header length.
AND if you use ddb for too long (months) it accumulates a lot of crap cookies!!!