UPDATED: What OS? What version of Firefox? I have Win11. Let me boot it up and I'll post a screenshot

Hello Jonzn, At the risk of sounding like I know everything, this thumbnail preview image was added by Firefox, in an update about three months ago. That thumbnail preview in my taskbar has never been there before, or I should say it never dropped down a thumbnail before

I'm using Windows 11 Pro. Version H2 (OS Build 22631, 4751. Computer is an HP Slimline Desktop - 290-p0056 --- It's about 2.5 yrs old.

Yeah, Jonzn, I've already been there, that doesn't work. "Show an image preview is "unchecked"

As far as I know, Windows has always generated thumbnail images for an application's open windows. I see this for Acrobat, Word, Outlook, etc., not just Firefox. But if I have too many windows open (a chronic condition), then I get a tall list of active tab titles instead of a row of images.

I don't know whether Firefox has a setting to avoid this. (The checkbox "Show tab previews in the Windows taskbar" is for choosing between just showing the active tab in each window, or EVERY tab in every window.)

If you don't want thumbnails for open windows, maybe there is a Windows 11 setting for that?