Originally Posted by
SJCFlyerLG
Recently, I cannot post images using Firefox on Windows 10. The upload tab is grayed out, and I have to close the Flyertalk tab.
No problem when using MS Edge browser.
Firefox 61.0.2
Windows 10 version 1803

This is a PNG image (I also tried successfully with jpg) uploaded with Firefox on Windows.
You may want to try clearing your FT cookies and browser cache.