I always automatically update when new versions come out & clear cache regularly, but just recently have notice that not all thumbnail images load on my gallery pages.
Thought it was because I had changed to a "cheaper" host and the data was not downloading quick enough, even though I have broadband.
Just had the bright idea to try the same pages using IE and everything works perfectly!
Anyway, getting back to missing thumbnail images, the page appears to be still loading with most of the images there, then it comes up "Done", but occasionally there will be one or more thumbnail images missing, with just the file name being displayed where the image should be.
Don't think I have any unusual settings or add-ons for Firefox.
Might give it a try. One thing though, it is slow on both the laptop & desktop computer.
Have been searching the internet, tried Firefox in safe mode, but still slow.
As an example, IE loads a page with 20 thumbnails within 2 seconds, but Firefox is still struggling after about 6 seconds & then gives up & says "Done" with maybe a thumbnail or more not showing. Same on bot computers.