Yes? Again, it's doing what you told it to do. It is *CHANGING* the title of the image. Which is, indeed, the title that shows up when you mouse over the image.
What do you mean by "want [the title] to pop up
You could just do
<img src="Picture 322.png" onclick="alert('New Title');" />
is very much obsolete nowadays. Some browsers allow the user to block alerts, so they are *NOT* a good way of giving messages.
So what kind of (other) pop up are you interested in?