http://kb.mozillazine.org/Images_or_animations_do_not_load

Thanks for the help. My husband worked on my computer for several hours to no avail. Post still smear or stretch. Guess time for a visit to the computer shop.

Start Firefox in Safe Mode {web Link} by holding down the <Shift>
(Mac=Options) key, and then starting Firefox. A small dialog should appear. Click Start In Safe Mode (not Refresh).

Is the problem still there?

Start your Computer in safe mode with networking. Then start Firefox. Try Safe websites. Is the problem still there?

Starting The Computer In Safe Mode;
Free Online Encyclopedia

Hi nancy1959, Firefox 49 has an incompatibility with some older graphics card/chipset driver software. Some users have reported that switching between tabs will cause Firefox to fix the display, but that's obviously not convenient to do all the time.

A bug report is on file (bug 1304360). You can help the developers working on the patch by providing some information about your current Graphics software (see below). Then try to fix it by updating your graphics software, or if necessary, work around it by turning off Firefox's use of hardware acceleration. Here are the detailed steps:

Your Current Graphics Software

You can copy/paste this info from the Troubleshooting Information page. There are 3 different options for opening that:

• "3-bar" menu button > "?" button > Troubleshooting Information
• (menu bar) Help > Troubleshooting Information
• type or paste about:support in the address bar and press Enter

On the left side, click the Copy Text to Clipboard button. Then paste into a new reply here:

https://support.mozilla.org/questions/1140937#question-reply

Before posting, please skim down and remove any lines that contain your email address or any other sensitive information (usually there isn't any, but just in case). You also can delete all the lines about printers if you like.

Updating Your Graphics Software

This article suggests safe ways to check whether graphics card/chipset driver updates are available for your system: Upgrade your graphics drivers to use hardware acceleration and WebGL. Unfortunately for some older systems, updates are just not available.

Working Around Incompatible Graphics Software

Option #1: Targeted Change

This should have the least performance impact, if it works:

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

(2) In the search box above the list, type or paste d3d and pause while the list is filtered

(3) Double-click the layers.allow-d3d9-fallback preference to switch the value from true to false

You might not notice any change until the next time you exit Firefox and start it up again.

Option #2: Disable Hardware Acceleration

This is a common way to bypass most graphics software incompatibilities, but may cause fonts to appear spindly and poor animation performance.

"3-bar" menu button (or Tools menu) > Options

In the left column, click Advanced. On the right side, with the "General" mini-tab active, uncheck the box for "Use hardware acceleration when available".

This takes effect the next time you exit Firefox and start it up again.