(Running 4.4.2) Some images have stopped loading? :(

Hey!
First time poster – sorry if i’ve done anything wrong!
I look after the website for the bar that I work in and I noticed yesterday that suddenly about half of the images are not working anymore? I’ve tried on two different computers and in different browsers.
It seems to affect images that i’ve uploaded to wordpress (as opposed to ones i just copied the url in for) but a few images i’ve uploaded are still working. It means my website looks like this http://www.nicensleazy.com/2665-2/ 🙁 🙁

All images seemed fine when they were uploaded first and this new problem now seems to be affecting images uploaded months ago!

I haven’t (knowingly) changed anything with plugins or themes or anything ever on the site so I have no idea why it’s started doing this! 🙁
Any help would be really appreciated!
(and don’t be afraid to be basic with me cos I don’t really know what I’m doing!)