You can't publish / save a post that has local images while offline.
When trying to save / publish a post with media from the camera roll an alert dialog displays:
Uploads failed / Some media uploads failed. This action will remove all failed media uploads from the post. Save anyway?
Not now and Yes are the options.
This was reproduced in Aztec, but not in Gutenberg.
None.
When I run the production app I see the described behavior with the alert showing up.
But when I run on develop I notice some weird behavior while offline. The post completely disappears when I update. Anybody else seeing this? @diegoreymendez , @shiki ??
Steps:

no longer seeing this issue (no blocking pop up alert) in develop.
Can you confirm? @diegoreymendez , @shiki ?
@yaelirub - I couldn't reproduce this either, but I looked into the code and this alert is still in there.
From what I could read, it seems to me like this may probably be hidden when the upload is async. I'm not sure the exact conditions cos I just briefly looked at it, but for reference @yaelirub, this is where the alert is being shown:
My suggestion on how to move forward:
My 2 cents... hope that helps.
I cannot reproduce it too. I agree with what Diego suggested.
I've been able to reproduce it once by "faking" a response from a server about a malformed image — so I don't think we can get rid of the whole logic just yet.
I have a work in progress patch based on #11933 to clean up the code around this a bit and make sure we'd only show that for cases where there's an actual actionable problem for users, not just a bad network connection. I'll PR it tomorrow!
fwiw, I tested with WPiOS 13.1.1 (App Store version) on iPhone 6S iOS 13.1 Beta 1 and found that I couldn't see the dialog saying it would remove the media as described in the issue:
Uploads failed
Some media uploads failed. This action will remove all failed media from the post. Save anyway?
Then the image uploaded normally for me after going back online. (2m22s)
I used the following testing steps:
- Be offline
- Go to published post in Aztec
- Add image to post
- Choose update
I also triple-quadruple confirmed this is no longer an issue — some of the patches we've been working on as part of Offline Posting fixed this already. Closing the issue.
Most helpful comment
I also triple-quadruple confirmed this is no longer an issue — some of the patches we've been working on as part of Offline Posting fixed this already. Closing the issue.