var lastImageChange;
function changeMainImage(Number){   
    var arrThumbs = strThumbs.split(";");
    var arrLarge = strLarge.split(";");

    if(lastImageChange==Number){
        Number = 0
    }

    // change large image 
    var imgObj = document.getElementById('productLargePic');
    imgObj.src = 'images/products/' + arrLarge[Number];
    
    // reset thumbnails 
    imgObj = document.getElementById('productThumbPic1');
    imgObj.src = 'images/products/' + arrThumbs[1];
    imgObj = document.getElementById('productThumbPic2');
    
    if(imgObj!=null){
        imgObj.src = 'images/products/' + arrThumbs[2];
         }

    // change thumbnail
    if(Number>0){
        imgObj = document.getElementById('productThumbPic' + Number);
        imgObj.src = 'images/products/' + arrThumbs[0];
    }
    
    lastImageChange = Number
    
}