[Conny Westh]

Om jag fattat din avvsikt så vill du använda "Modulus"....

int iCount = 100;

        string sHtml = "<table cellpadding='0' cellspacing='0' border='0'>";

        for (int i = 1; i < iCount + 1; i++)
        {
            if (((i-1) % 20) == 0)
                sHtml += "<tr>";

            sHtml += "<td>";
            sHtml += "<img src='http://lorempixel.com/100/100/people/' style='margin-top:-3px'>";
            sHtml += "</td>";

            if (i % 20 == 0 )
                sHtml += "</tr>";
        }
        sHtml += "</table>";

        LiteralImageGrid.Text = sHtml;