I've had this problem as well with posting pictures in my posts. When you use the function "picture upload" and then added the files for upload. The processing icon that circles with the dots would pop up a split second and then disappears. Having done this multiple times sometimes the upload would get through, and you can add the pictures in your post. Very annoying... Sometimes i would need to do this like 10 times before it worked. I have a solution that worked for me:
Disabling the add-block in your web browser on this website and give it permission. Hope this helps.
-Dos
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