Hack like this one
 

Hello
I need something like that:
http://www.customaniacs.org/forum/custom-coversets/

Descrption: image included as first image in post is display as thumbnail next to thread title.

Which hack will be good for me?

Thumbnail image icons.
That hack is here already. Forgot what it is called.

Try Attachment Thumbnails on FORUMDISPLAY.

can not find...can someone help me?

Refresh, can someone help me find it (for 3.8)

Here you go, I remembered who made it as opposed to what it was called, managed to find by searching their User Name!

Thread Thumbnails by Null Parameter