var nowPrev = 1;

function modelImage(num, photo) {
document.getElementById('bigPhoto').src = '/images/content/' + photo;

document.getElementById('preview' + nowPrev).className = 'prev';
nowPrev = num;
document.getElementById('preview' + nowPrev).className = 'prev sel';
}

function showImage(img, txt) {
document.getElementById('bigPhoto').src = img;
document.getElementById('photoName').innerHTML = txt;
showPop();
}