Express checkout button image intermittently 404 not found?

[Princessly_com]

Please see one of our product pages: https://www.princessly.com/sheer-neck-peach-pink-tulle-ivory-lace-wedding-flower-girl-dress-with-bea...

If you refresh the page, sometimes the paypal express check out button image would not display and if you open the button image in a new browser window, it's 404 error.

But sometimes it's fine while others times it's not. It seems it's some kind of protection mechanism on PayPal server or something that's intermittently triggered?

Has anyone had this issue before? It's really weird. 

How can I make sure this doesn't happen to my customers? It would definitely drive down sales I believe.

[GHT_Kristian]

Posted May and no response?!

Can't find another occurrence yet it happens to me all the time.

Thought there'd be an easy solution.

Anyone with any thoughts on why this is happening - just as OP describes?