Uploading the images again likely won't help. This is about how the images are requested.

If you use explicit http: links on your web page then omit this protocol and only leave the // to make Firefox use the default protocol assuming that the images can be retrieved via HTTPS.

You can check the Web Console and Network Monitor for more detail.

• "3-bar" menu button or Tools -> Web Developer

Just to clarify: by default, Firefox does not block HTTP-address images in an HTTPS-address page. It just puts a warning triangle on the padlock.

If Firefox says it is blocking content, it might be blocking other kinds of content in the page such as scripts.

As cor-el suggests, when you first start accessing a site on HTTPS, you discover a lot of URLs that are hard coded for HTTP and that may include scripts, style sheets, images, and other things. For more information on how to use the Web Console, see:

https://developer.mozilla.org/docs/Tools/Web_Console

After opening that, I suggest reloading the page to get a full list of messages. Then in the box above the console conents, upper right, which says "Filter output" you can type mixed to quickly isolate messages about mixed content.