I posted a question yesterday but after further investigation I narrowed it down to a drag and drop issue so I'd like to post this as a separate question and I'll look at closing the other one.
I'm using Confluence 5.7 on my Windows Server 2012 R2 setup as I've been running over a year. This issue has been occurring for a few releases now, it's not a 5.7 specific issue I believe. It is not specific to a browser or operating system as some of my users use Mac and others Windows. I can duplicate this with my Mac using Safari though, if that matters.
Create a new blank page and drag and drop a PNG image into it. Save the page, it shows fine. I can check from other computers and as long as I'm logged in as me the image will appear. If I login as a test user (member of only jira-users) (and yes, I'm using JIRA for user management) I see a broken image. If I click the paper clip at the top I see the attachments listed, if I click it I get an error message. Images are stored in the file system since storing in the database is now deprecated, we used the database before, same problem.
I've been over the installation notes over and over, checked permissions, etc. I'm not sure what to check or how to fix or if this is purely a bug in confluence. I was thinking maybe IUSR needs write permission because it's Windows but then I thought no, that's IIS and this is not running under IIS.
We prefer drag and drop images but the only thing that works properly is to use the INSERT toolbar option, then it works correctly.
Thank you.