var pictureCount = 1;
var pictureMin = 1;
var pictureMax = 15;

function galleryNext()
{
    ++pictureCount;
    if (pictureCount > pictureMax)
    {
        pictureCount = pictureMin;
    }
	document.getElementById('pictureBox').innerHTML = '<img id="galleryPicture" src="gallery/gallery_'+pictureCount+'.jpg" alt="Gallery Image '+pictureCount+'" title="Gallery Image '+pictureCount+'"/>';
}

function galleryPrev()
{
    --pictureCount;
    if (pictureCount < pictureMin)
    {
        pictureCount = pictureMax;
    }
	document.getElementById('pictureBox').innerHTML = '<img id="galleryPicture" src="gallery/gallery_'+pictureCount+'.jpg" alt="Gallery Image '+pictureCount+'" title="Gallery Image '+pictureCount+'"/>';
}