How to show waiting image in aspx

hello,
i have two pages one page1.aspx and page2.aspx
page2.aspx have heavy data load on page_load event
now page1.aspx i have run and one button n click n redirect to page2.aspx
now its wait on page1.aspx until page2.aspx load complete then its come page2.aspx
so

i have to show a wait image when page redirect its can be waiting page or other this but i dont find some solution

have any idea ?