hello MarceloDelgado, the firefox picture appears bigger, so maybe it's zoomed in? please try to press ctrl+0 on the affected site to make sure that the zoom level is reset to 100%.

in case the same issue is happening everywhere, please make sure that you have set windows to display at 100% in the windows control panel > appearance > display. more information about that is available at http://windows.microsoft.com/en-us/windows7/make-the-text-on-your-screen-larger-or-smaller

Hi philipp. You're right, I never noticed the difference in size. Indeed the display is showing elements at a greater measure (105%). And indeed changing it to 100% has fixed the problems with images, but at the cost of reducing text size everywhere else!

The reason I use a slightly higher font size in Windows Aero is because my display's current DPI at native resolution is high enough for this display size to give me problems reading text adding an unnecessary strain to my eyes. The slightly larger font size helps greatly in reducing this problem.

Firefox hasn't blurred images forever, meaning there was a change introduced to make this happen. Other browsers do not do this either, I can see fonts as I need them to, and images are presented crystal clear too. So, is there a way I can change Firefox's configuration in order to ignore this Windows setting for images?

Changing Firefox's zoom behavior so you can enlarge just the text but not the images can lead to site layouts breaking. If you want to take a look:

View menu > Zoom > check Zoom Text Only

(If you do not normally display the classic menu bar, tap the Alt key to display it temporarily.)

Firefox 22 was the first to tie your Firefox content zoom level to your Windows DPI setting. You can break the connection and set Firefox to use 100% resolution (the classic 96dpi resolution) if you like. Here's how:

(1) In a new tab, type or paste about:config in the address bar and press Enter. Click the button promising to be careful.

(2) In the filter box, type or paste pix and pause while the list is filtered

(3) Double-click layout.css.devPixelsPerPx and change its value to 1.0 for Firefox 21-sized fonts.

This will return the content to normal, but the toolbars may appear a bit smaller than your Windows standard for UI (100%/105%). There is an extension to enlarge fonts in that area: Theme Font & Size Changer.

Can you get it to work the way you want?

Hi jscher2000,

Thanks! I've changed the value of layout.css.devPixelsPerPx as you indicated and I'm now using the Theme Font & Size changer plugin, with a font size one point larger than default, which is exactly how I want Firefox to show pages. Images now look crisp.

I suppose my problem is solved now. Thanks to both of you for pinpointing the problem and coming with a solution! :)