function changePhoto(src, caption, width, height) {
    img = document.getElementById('mainPhoto')
    caption_div = document.getElementById('mainPhotoCaption')

    if (!img || !caption_div)
        return false

    if (img.src == src)
        return true

    img.src = src
    img.alt = caption
    img.width = width
    img.height = height
    caption_div.innerHTML = caption

    printable = document.getElementById('printablePhoto')

    if (!printable)
        return true;

    printable.src = src
    printable.alt = caption
    printable.width = width * 480 / 640
    printable.height = height * 480 / 640

    return true
}