how to aaply onclick event on a image in repeater

You should define image in repeater itemdatabound.
And then you can give events to image.

In repeater you can define like
HtmlImage img = e.item.FindControl("img") as HtmlImage;
or
Image img = e.item.FindControl("img") as Image;

thanks for your help
i have done it like this

 protected void rptthumbimg_ItemDataBound(object sender, RepeaterItemEventArgs e)
    {
        if (e.Item.ItemType == ListItemType.Item)
        {
            DataRowView drv = (DataRowView)e.Item.DataItem;
            dt = obj.searchimg(4, imgcatid);
            if (dt != null)
            {
                Image imgmem = (Image)e.Item.FindControl("imgthumb");
                if (dt.Rows.Count > 0)
                {
                    if (dt.Rows[0]["thumbnail"].ToString() == "")
                    {
                        imgmem.ImageUrl = impplaces + "memimg.png";
                    }
                    else
                    {
                        imgmem.ImageUrl = impplaces + dt.Rows[0]["thumbnail"].ToString();
                    }
                }
            }
        }
    }

i want to implement onclick event on this image and i dont know hoe to do it.

imgmem.Attributes.Add("onclick", "eventname");

thank you very much for all ur help.it was really helpfull to me.