I suspect your Firefox is working as designed.

Firefox no longer uses 96 pixels per inch as the baseline zoom level. Instead, it often uses a larger baseline zoom level based on your Windows "Text Size" percentage (such as 120ppi, which is 125% of 96ppi). The fact that you get the expected size after zooming out twice, which brings Firefox's zoom level to roughly 80%, would be consistent with this theory.

It would be nice if there was a way to counteract this when you're viewing "stand-alone" images -- reserving zoom for web pages -- but I'm not aware of any built-in way to do that. Perhaps an add-on could do it?

If you found everything too large in Firefox, you could globally counteract the "text size" effect using an extension that lowers the base zoom level to 80%. For example:

• Default FullZoom Level
• Zoom Page (includes "fit to window" feature)

After setting your global or default zoom level, you can still fine-tune the zoom on individual sites using Firefox's standard zoom feature (keyboard shortcut or mouse wheel).

Hi jscher2000

I went into windows display > set 100% since it was at 125% as you mentioned and Firefox seems to be showing the image correctly. Now I can click the magnifying glass zoomer + and - and the image shows correctly.

Crazy thing is that I made that display setting change in windows (7) to 125% a long time ago since I got a new 2560x1440 monitor and the resizing issue just happened recently. Probably with a FF update. But as you mentioned it's a new default FF value now.

But I am also checking out the two extensions you mentioned and will work with them some and fiddle. I'm in the right direction now of getting it fixed so thanks for the info!

I'll go ahead and mark this issue solved since technically I did change something and it did fix after your recommendation!

Cheers...!