display picture(url) from db into a picturebox in datagrid?

Question

Hi
I have a datGridView on my from which gets the data from my dataset
i have changed the photo field to a pictureBox
but i do not know how to disolay the photo
It will be a hyperlink like this:http://www.mysite.com/ + photoField
in which Event of datagrid should i get the info?
i need code pls