I think you wanted to display the form, not trigger a click event on it. You can try this following code for that,
$("#gallery").click(function() {
$("#FileUpload1").show();
});
More specifically (since you're hiding the element parenting this control then the code would be like)
$("#gallery").click(function() {
$("#FileUpload1").parent().show();
});
Above code would change the display property of the element that matches this selection; selection is the element that is parenting the element with the ID FileUpload1. The jQuery parent function can be read about
here[
^].
In jQuery the
click[
^] function, triggers a click event. It might not be noticable through the GUI, but the underlying code would trigger as if an actual mouse click were triggered over the element.