i have this code:
     var getFoto = function(value, metadata, record, rowIndex, colIndex, store) {
        var qtip = String.format('<img src="getImageCategorie.aspx?ID={0}" id="foto_' + record.id + '" />', record.id);
        return String.format("<img style='width:55px; height:55px' ext:qtitle='" + record.get('descrizione') + "' ext:qtip='" + qtip + "' src='getImageCategorie.aspx?ID={0}' id='foto_" + record.id + "' />", record.id);
    }
it's possibile set the width of the toolitp ? "ext:qtip"

regards