rygel-12.6 image rendering error

[John Frankish <j-frankish slb com>]

The rygel-12.6 release notes say:

Playbin:
  - Add possibility to render images.

This works:

$ gst-launch filesrc location=/mnt/sda4/media/image/image.jpg ! jpegdec ! ffmpegcolorspace ! freeze ! autovideosink

This works (image flashes on screen):

$ gst-launch playbin uri=file:///mnt/sda4/media/image/image.jpg

..but using rygel-12.6 and gupnp-av-cp: (video and music works fine) things do not work

$ rygel
...
MediaExport-Message: 'file:///mnt/sda4/media' harvested
GLib-GIO-Message: Using the 'memory' GSettings backend.  Your settings will not be saved or shared with other applications.

(rygel:13160): Rygel-WARNING **: rygel-http-request.vala:90: Streaming mode not supported for '3fc162dbf4cecdfdc336ba6ccaba6fa2'

(rygel:13160): Playbin-WARNING **: rygel-playbin-player.vala:202: Error from GStreamer element playbin20: gstsouphttpsrc.c(1117): gst_soup_http_src_parse_status (): /GstPlayBin2:playbin20/GstURIDecodeBin:uridecodebin1/GstSoupHTTPSrc:source:
Not Acceptable (406), URL: http://192.168.1.100:53217/MediaExport/i/M2ZjMTYyZGJmNGNlY2RmZGMzMzZiYTZjY2FiYTZmYTI%3D

(rygel:13160): Playbin-WARNING **: rygel-playbin-player.vala:205: Going to STOPPED state