PUBAPI-1227: document the inconsistency that ListMachines shows *docker* instances, but ListImages does NOT show docker images

CHANGES.md

@@ -2,7 +2,8 @@
 
 ## 4.3.2 (not yet released)
 
-(nothing yet)
+- PUBAPI-1227: Note that `triton image list` doesn't include Docker images, at
+  least currently.
 
 
 ## 4.3.1

lib/do_image/do_list.js

@@ -126,6 +126,10 @@ do_list.help = [
     /* BEGIN JSSTYLED */
     'List images.',
     '',
+    'Note: Currently, *docker* images are not included in this endpoint\'s responses.',
+    'You must use `docker images` against the Docker service for this data center.',
+    'See <https://apidocs.joyent.com/docker>.',
+    '',
     'Usage:',
     '    {{name}} list [<options>] [<filters>]',
     '',