Question

is possible this wrote simple, code is here:

foreach (var friend in friends)
{
    friend.Value.blockQuote = GetBlockQuote(friend.Value.nick);

    if (friend.Value.photo == "0")
    {
        if (friend.Value.sex == 1)
        {
            var img = new BitmapImage();
            img.BeginInit();
            img.UriSource = new Uri(@"avatars\man.jpg",
                                    UriKind.Relative);
            img.EndInit();
            friend.Value.profilePhoto = img;
        }
        if (friend.Value.sex == 2)
        {
            //da default
            var img = new BitmapImage();
            img.BeginInit();
            img.UriSource = new Uri(@"avatars\woman.jpg",
                                    UriKind.Relative);
            img.EndInit();
            friend.Value.profilePhoto = img;
        }
    }
    else
    {
        var img = new BitmapImage();
        img.BeginInit();
        img.UriSource = new Uri(friend.Value.photo.Replace(@"\", "").Replace(@"s_", ""), UriKind.Absolute);
        img.EndInit();
        friend.Value.profilePhoto = img;
    }
}

Answer 1

Break out the uri-setting part

foreach (var friend in friends)
{
    friend.Value.blockQuote = GetBlockQuote(friend.Value.nick);

    Uri uri;
    if (friend.Value.photo == "0")
    {
        if (friend.Value.sex == 1)
        {
            uri = new Uri(@"avatars\man.jpg", UriKind.Relative);
        }
        else if (friend.Value.sex == 2)
        {
            //da default
            uri = new Uri(@"avatars\woman.jpg", UriKind.Relative);
        }
        else
        {
            uri = null; // insert error handling here
        }
    }
    else
    {
        uri = new Uri(friend.Value.photo.Replace(@"\", "").Replace(@"s_", ""), UriKind.Absolute);
    }
    var img = new BitmapImage();
    img.BeginInit();
    img.UriSource = uri;
    img.EndInit();
    friend.Value.profilePhoto = img;
}

Edit
Note that the if-else-part is now a good candidate for Refactor->Extract method