/**
 *
 * pops up maximised
 **/
function enlargeImage()
{
    window.open(document.getElementById('mainimage').src, 'popupEnlargeImage','menubar=no,toolbar=no,width=640,height=640');
}
/**
 *
 * swaps main image
 **/
function swapMainImage(xSwapID)
{
    var oSwap = document.getElementById(xSwapID);
    var oMain = document.getElementById('mainimage');
    var szTemp;

    if((oSwap) && (oMain))
    {
        szTemp = oMain.src;
        oMain.src = getfullimage(oSwap.src);
        oSwap.src = getthumbnail(szTemp);
    }
}

/**
 *
 * gets relative thumbnail
 **/
function getthumbnail(xImage)
{
    var szThumbnailImage = xImage;
    var arrImageParts = xImage.split('/');
    var ilastpart;
    var szFilename;

    if(arrImageParts.length > 1)
    {
        ilastpart = arrImageParts.length - 1;
        szFilename = 'thumb_' + arrImageParts[ilastpart];
        szThumbnailImage = '';

        for(var i=0; i < arrImageParts.length - 1; i++)
        {
            szThumbnailImage += arrImageParts[i] + '/';
        }

        szThumbnailImage += szFilename;
    }

    return szThumbnailImage;
}

/**
 *
 * gets full image from thumbnail
 **/
function getfullimage(xImage)
{
    var szFullImage = xImage;
    var arrImageParts = xImage.split('/');
    var ilastpart;
    var szFilename;

    if(arrImageParts.length > 1)
    {
        ilastpart = arrImageParts.length - 1;
        szFilename = (arrImageParts[ilastpart]).substr(6);
        szFullImage = '';

        for(var i=0; i < arrImageParts.length - 1; i++)
        {
            szFullImage += arrImageParts[i] + '/';
        }

        szFullImage += szFilename;
    }

    return szFullImage;
}