All of a sudden the pictures on my website have dissapeared leaving empty boxes.

The problem is that instead of reading
Code:
"http://www.mywebsite.com/images/pic1.jpg"
it reads as:
Code:
"https://www.mywebsite.com/images/pic1.jpg"
the https has applied itself to all of them. I don't remember is this was always the case as I have not altered the site for months.

Tell me what to do about it.
Thanks