When you are displaying just the image and not web page with image embedded in it, instead of using Save Image As, try using Save Page As

(MAC) command+s
(WIN) Ctrl+s

By the way, another option for saving images is

Tools > Page Info > Media tab > {select from list} > Save As button

This dialog can work around a lot of obstacles.

Thanks. That works, but does this mean that "Save Image As" is broken for certain situations?

I use an Add-on called "Save File to" that uses "Save Image As", speeding up folder navigation. I'd like to have that working properly again, if possible.

Try to clear the cache and the cookies from sites that cause problems.

"Clear the Cache":

• Firefox > Preferences > Advanced > Network > Offline Storage (Cache): "Clear Now"

"Remove Cookies" from sites causing problems:

• Firefox > Preferences > Privacy > Cookies: "Show Cookies"

Start Firefox in Safe Mode to check if one of the extensions or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance/Themes).

• Don't make any changes on the Safe mode start window.
• https://support.mozilla.org/kb/Safe+Mode

See also:

• http://kb.mozillazine.org/File_types_and_download_actions

I believe this may the bug here, but on Firefox for Mac in my case. https://bugzilla.mozilla.org/show_bug.cgi?id=715010

Okay, with the Save File to add-on, you want to use Save Page to. In order to enable that, you need to click in the black area above or to the left (or to the right or bottom) of the image.

If the image is fully zoomed, click the image once to fit it inside the browser viewport, and at least some outside area should be visible. In the rare case that the image is a perfect fit, then you'll have to use one of the other options, or change the shape of the window.

So simple, I should have seen it. A perfect work-around, thank you!