If you are experiencing difficulty downloading or viewing images through Firefox, follow the troubleshooting instructions below.

This article applies to:

• Still image file formats such as PNG, GIF, and JPG

• Animated file formats like animated GIF

This article does not apply to the following formats: 

• Video, such as MPG, WMV, and AVI. For more information, see Fix common audio and video issues.

• Animated content that is displayed through a plugin, such as the Flash plugin. Learn more in Flash Plugin - Keep it up to date and troubleshoot problems.

Note: If you're having trouble with a website, click the icon in the address bar to see if Firefox has blocked parts of the page that are not secure. See Mixed content blocking in Firefox for details.

https://support.mozilla.org/en-US/kb/fix-problems-images-not-show

Pallavi ... Thank you so much for this information .. I tried them, with still no success getting the photo Thumbnails to display .. BUT THEN .. accidentally I discovered there is some conflict between Microsoft One Drive backup and the Thumbnails not appearing .. for lack of space reasons, I un-linked my One Drive account with my laptop backup and by surprise all the photo Thumbnails that had not been present suddenly displayed ... That never happened in my previous HP Laptop, I never had that problem .. I'm not sure what the conflict is/was, but now, not using One Drive backup has eliminated the Thumbnail display problem .. Thanks for your response .. it taught me a few other things I did not know ... :)

hello Sammy,

follow the link

Thumbnail picture icons only display generic icon - Windows 7 - Tom's Hardware Thumbnails not appearing for large icons on Windows 7 (NAS Drive) - Microsoft Community

tell me its help