Trouble posting photos today

I have uploaded many photos over the years with the Attachment Manager , some even 1920 x 1080 pixels and 150 kB in size, reduced from 4000 x 2280 pixels and 2.5MB.

Today I went to post six pics, all 854 x 479 pixels, file sizes 32 - 54 kB, but the red exclamation mark appears against each file when I try to upload these tiny files, and I cannot progress any further.

Is there a problem with the Attachment Manager today, or do I need to further reduce the sizes?

Have tried posting screen print of the failure, even resized it down to 799 x 449, and then removed my Kaspersky Internet Security and tried to attach image using Firefox that I have always used. Still got the same red exclamation mark indicating error

Test upload

Image is 65.9kb - 800x500

Using Firefox

Pics in post. PM sent.

:U