That depends on where you uploaded them to before inserting them in your posts. Some free storage servers might sometimes delete or change their file names for some reason.

For example, I used to save my images on Google Picasa and when they changed their service settings and my images disappeared too.

Just check if they are still on where you saved them and then re-insert them in your posts.

Do you have a backup of your website?
If yes then you can recover it from the backup.

That's odd Bill. If you upload the images and store them in your media library then they should always be there. If they are hosted elsewhere and displayed with shortcode then I guess the hosting site can move them then they won't appear on your site anymore. Sound slike you may have to re-insert them. Hope it's not too many.

I didn't entirely understand what you mean. Can you take a screenshot and show us? Or explain what's going on with more detail?

Some time things like this happens with electronic devices, software etc. Some time we don't even know why. But the solution is:
Just take a break with it for some time. Come again later and you'll see it working by itself.

Give it a try and keep us updated. thx.

Thanks for the reply. The thing is when I put my website in both the firefox and chrome browser, it comes up. Then when you click on it, the message I indicated shows up.

Try it with http: see if that helps