Taking the fact that Imgur is having problems with their service, can we address the actual ingame issue, with screenshot being uploaded to flickr (respectable photo hosting btw too)
Please avoid using the Flickr URL when uploading your screenshot to imgur.
Instead, go to your game’s folder and open the "Screenshots" folder. then, you can either drag and drop the image directly into Imgur or click the "Choose Photo/Video" option on Imgur and select the screenshot manually.
You also mentioned an issue with Imgur. This can often be resolved by using a VPN.
However, keep in mind that some free VPNs are commonly used for botting, which may lead to account IP ban. To stay safe, use the VPN only while uploading the screenshots, then disable it before logging back into the game.
I mean I've tried everything VPN ON, VPN OFF, Drag and drop, upload via file selection, upload via link, pasting binary data from a buffer (Ctrl + V), etc. Previously, it was working, and I've successfully submitted a report with Imgur link. Now, it does not.
Sounds logical, right? :D Image quality from flikr (the link that I've provided in the ticket) is crystal clear (full native 1080p resolution), but still required to upload to the service that I'm unable to... :(