I think the issue might be from my browser, maybe I might have messed up with settings or something that lead to the repeated error message.
I just tried same image all three using my Mozilla Firefox and it works just fine.
I also tried uploading them, and it worked. No issue!
Yeah most likely your browser is at fault here. Note that when you keep the talkimg tab open in the background along with other tabs (without using it), many times, this upload error would show (something to do with credentials getting expired). Can you confirm this was not the case? The common fix here was refreshing the tab and clearing the cache.
