Is there any particular reason that image_proc and image_view use so
much cpu?

CPU0: Intel(R) Core(TM)2 Duo CPU     T5270  @ 1.40GHz stepping 0d

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+
COMMAND            
12247 user      20   0  101m  18m  12m S   15  0.9   0:09.97
image_view         
12249 user      20   0  101m  18m  12m S   15  0.9   0:09.10
image_view         
12248 user      20   0 99.1m  15m 9740 S   15  0.8   0:11.15
image_proc         
12246 user      20   0 95528  26m  10m S   13  1.3   0:08.27
usb_cam_node  

Is this mostly messaging overhead that could be fixed by moving to
nodelets? Has there been much work been done to optimize the nodes
within the image_pipeline package?