1 - Install Optware New Generation from here
2 - Disable stock Minidlna from here
3 - Install minidlna with thumbnails support
4 - Edit configuration file and change server name if you wish, change media directory or leave as default and all drives will be scanned
Save with CTRL-O / Enter / and exit with CTRL-X
5 - Start minidlna media server
6 - Go to www.asusrouter.com:8200 and see how minidlna is creating db, press refresh on your browser for progress.
This is how it looks like on my Samsung TV with thumbnails and filmstrip enabled
If for some reason you don't like default penguin minidlna icon, you can choose any icon as minidlna logo, thanks @R.L.Horn :)
7 - Copy some favorite icons (.png format) to /mnt/sda1/icons/ for example
8- Edit minidlna.conf
Find this line, uncomment and replace with the path to your desired icon
9 - Restart minidlna
A huge thanks @alllexx for porting minidlna with thumbnails support
Enjoy watching movies on Samsung tv's and not only...
Please share feedback with your tv model!