Forum Discussion
Why are files in SiteCollectionImages in SharePoint Online (O365) anonymous for all tenants?
I just found that files of type images (.jpg, png) or .js files located in anyone's O365 tenant are served with no prompt for authentication. Just wondering if this was done for performance reason in...
I suspect this is related in some way to something Chris O'Brien discovered long ago with regard to the assets that are served from SharePoint's BLOB cache (http://www.sharepointnutsandbolts.com/2009/05/optimization-blob-caching-and-http-304s.html). It's not a direct match, but consider the mechanisms in-play and whether or not you previously authenticated to the site and had BLOB cache assets served to you.
If someone wants to capture a browser trace (with Fiddler, a browser using dev tools, etc), I'd be happy to look at it and see if I could make heads or tails of it :-)
- Sean