The forum limits attachments to 4MB but this is typically not big enough to allow a 1440p screenshot to be uploaded - which is necessary for a good bug report.
I suggest increasing this limit to allow a 4K screenshot to be uploaded, plus a bit more for log files.
Majority just get around this by using imgur; posting a link. Also you can link YouTube videos if you have a bug recorded and want to show it like that. The file limit is just big enough to post crash files, might be set up like this on purpose to get people to not upload a lot.