Lync monitoring reports - images are missing

After some analysis we found an error in SSRS logs:

reportrendering!ReportServer_0-137!ffc!06/10/2015-12:33:19:: e ERROR: Throwing Microsoft.ReportingServices.ReportProcessing.RenderingObjectModelException: , Microsoft.ReportingServices.ReportProcessing.RenderingObjectModelException: A generic error occurred in GDI+. ---> System.Runtime.InteropServices.ExternalException: A generic error occurred in GDI+.

   at System.Drawing.Image.Save(Stream stream, ImageCodecInfo encoder, EncoderParameters encoderParams)

   at Microsoft.Reporting.Chart.WebForms.Chart.Save(Stream imageStream, ChartImageFormat format)

   at Microsoft.ReportingServices.OnDemandReportRendering.ChartMapper.GetImage(ImageType imageType)

   --- End of inner exception stack trace ---;

Apparently gdiplus.dll was not up-to-date on the SQL SSRS server. After Windows 2012 R2 patching the problem was solved.