You didn't include the #help in here ;)

See the help-channel on the chat, those who know more about the technical details of Steemit are there, but not 24/7 but you can check later for replies:
https://steem.chat/channel/help

The error you've got isn't something common, or at least I haven't seen it before.

If you want a cheat solution, switch from Steemit to Steempeak.com, it's a different UI and the images are uploaded to steempeak servers instead of Steemit ones. Their website seems to be more stable.

Both work on the Steem blockchain, so same accounts & same content is visible and your post is seen on both sites.