It's bobbins
- The Digital Millennium Copyright Act is about copyright; trademarks and copyright are not the same thing at all
- any reputable lawyer would state up front which trademarks are being infringed
- 'unauthorized display of a registered trademark, which is prohibited for public sharing online without prior written permission' is legal bunkum.
- you have to reply before they will tell you what photo infringes their trademark?! No, it just means they are fishing to see who will bite
- it implies that the message is from Flickr itself; but Flickr don't do trademark enforcement
- the email address is nonsense, it's not a Flickr account and bears no relation to the Flickr account holder sending the message
Delete and forget
Edit: better still, it's a scam - report the account to Flickr