why don't you do:
function logoChange1() {
logo.setAttribute("src", "images/picture1");
};
function logoChange2() {
logo.setAttribute("src", "images/picture2");
};
or just change the src
property:
function logoChange1() {
logo.src = "images/picture1";
};
function logoChange2() {
logo.src = "images/picture2";
};