See Check image permissions in this support article:
https://support.mozilla.com/en-US/kb/Images+or+animations+do+not+show

Can you post a link to a specific page if the page doesn't require authentication (log in) to access it?

I solved this by reloading all the images It was not working on Firefox or IE before I did that. However another page had working gifs so I figure the gif files were at fault.

From your own solution, what you probably need to do is the clear cache more often. Especially when working with your own webpages. Along with updating your site so it matches what is on your computer.

• Tools > Options > Advanced > "Clear Now"
• I clear mine at the end of the session as set up from Tools > Options > Privacy

  http://img232.imageshack.us/img232/4928/clearcachew.png

To refresh a page use "F5", but to refresh bypassing cache use "Ctrl+F5"

• http://dmcritchie.mvps.org/firefox/keyboard.htm
• https://support.mozilla.com/kb/Keyboard%20shortcuts

If the images were broken then clearing the cache won't help at all and new and working images needed to be uploaded like the OP did.

@cor-el, I took it to mean that it is his website and he is changing things around, including images. Updated images are the last things that get seen by the developer because he already has something in cache, he changed it, knows he changed it, and doesn't see the changes.

Firefox seems to also have a problem updating local views where a fragment id is involved in the location bar, I'm used to always seeing a local file get refreshed immediately. If that happens remove the fragment-id reload and refresh bypassing cache.

Yes, I know, but it doesn't seem to apply to this case looking at the reply by the OP.

A reload with a cache bypass should be sufficient to refresh images from the server.