Make a popup warning about trying to upload image without origin tags.

[HushedFox]

Is your feature request related to a problem? Please describe.
Sometimes I forget to add any artist tags because they are added automatically from Twitter but not from FA and when I'm uploading from both alternately then it can happen sometimes.

Describe the solution you'd like
There should be a warning that tells the user that they didn't provide any origin tags. It should be triggered when either tags from category:origin or the tags artist needed or photographer needed are missing on an image.

It should only serve as an information, because it should still possible to upload image without any artist tags.

Here is my crude visualization:

Cancel would just make the popup disappear and would enable editing the tags and trying again
Continue would proceed with uploading with no changes to tags

If meaning of that Cancel is not clear enough it can be replaced with Go back to upload form, Correct tags, Add missing tags or maybe simple Close

Describe alternatives you've considered
That's the only viable solution.