var oImageClick = null;

function overImage(oImage) {
    oImage.src = oImage.src2;
}
function outImage(oImage) {
    if (oImage != oImageClick)
        oImage.src = oImage.src1;
}
function clickImage(oImage) {
    if (oImageClick != null) {
        oImageClick.src = oImageClick.src1;
    }
    oImage.src = oImage.src2;
    oImageClick = oImage;
}