Chart images not rendering in ReportList thumbnails is a server configuration issue.
Desktop Experience server feature contains the WebDAV redirector:
Microsoft has created a new WebDAV extension module that has been completely rewritten for Windows Server >2008, Windows Server 2008 R2, and Windows Server 2012. This new WebDAV extension module incorporates many new >features that enable web authors to publish content better than before.
Please enable 'Desktop Experience' within the server features to take advantage of WebDAV.
Last edited by Joseph Adams, 2014-04-02 14:05:14