netrender

jpeg versions of the render results are downloadable from the web interface. 

Notes:

1) They are generated (and written to disk) on demand on the master in the same Blender instance, so this will increase memory usage (until there's a way to free and image buffer from memory or it's run in a separate process).
2) They are darker then the real results, since multilayer exr contain the result before gamma correction (for the linear workflow) and that's not applied when loading them as an image.
3) They are NOT thumbnails, they are the same size as the results (albeit at 90% quality jpeg compression)

release/scripts/io/netrender/utils.py

@@ -148,8 +148,8 @@ def fileURL(job_id, file_index):
 def logURL(job_id, frame_number):
     return "/log_%s_%i.log" % (job_id, frame_number)
 
-def renderURL(job_id, frame_number):
-    return "/render_%s_%i.exr" % (job_id, frame_number)
+def renderURL(job_id, frame_number, exr = True):
+    return "/render_%s_%i.%s" % (job_id, frame_number, "exr" if exr else "jpg")
 
 def cancelURL(job_id):
     return "/cancel_%s" % (job_id)