the question is : Google Analytics change stats of my page if I do some changes on it ?
I don't know how G.A works when we update manually a page (html) For example, if I add a new picture to my gallery, Stats will change or not ?
If you are asking if it will start from scratch again, the answer is no: GA collects data based on the URL. Until that changes, GA will keep collecting data.
If you meant if the actual stats would change, they probably would but that wont be down to GA really. (Loading time changes, visitor retention might improve if it's a nice pic, decrease if it's a disgusting pic, etc etc)
If I did not get what you were asking, please clarify further so I can improve my answer.