I just noticed that I have a node that is emitting a bunch of messages
into its logfile:

...
[roscpp_internal] [2010-04-16 14:33:28,734] [thread 0xb776c980]:
[DEBUG] XML-RPC call [searchParam] returned an error (-1): [Cannot
find parameter [compressed_image_transport_format] in an upwards
search]
[roscpp_internal] [2010-04-16 14:33:29,228] [thread 0xb776c980]:
[DEBUG] XML-RPC call [searchParam] returned an error (-1): [Cannot
find parameter [compressed_image_transport_format] in an upwards
search]
[roscpp_internal] [2010-04-16 14:33:29,723] [thread 0xb776c980]:
[DEBUG] XML-RPC call [searchParam] returned an error (-1): [Cannot
find parameter [compressed_image_transport_format] in an upwards
search]
[roscpp_internal] [2010-04-16 14:33:30,219] [thread 0xb776c980]:
[DEBUG] XML-RPC call [searchParam] returned an error (-1): [Cannot
find parameter [compressed_image_transport_format] in an upwards
search]
...

I don't think I am doing anything with the
compressed_image_transport_format; the default jpeg is fine and that
seems to be what the node is producing.

Pat