Hi,

is it possible to serve the pictures from k2/media/item/cache from a subdomain?

I saw a thread here in the forum, bt without a solution. Hope there is a solution.

Thx

It is, I have not done it but it is.
You can use an extension or you can ask your hosting provider, how to treat a subcategory as a subdomain. Then you can use a system plugin to update the k2/media/item/cache paths to the new structure.
As you might have imagined if there is an extension it will save you a lot of time.