The API method configuration.export accepts the parameter "option" with the objects to be exported.

The options object has the following parameters according to the documentation:
groups - (array) IDs of host groups to export;
hosts - (array) IDs of hosts to export;
images - (array) IDs of images to export;
maps - (array) IDs of maps to export.
screens - (array) IDs of screens to export;
templates - (array) IDs of templates to export;

When trying to export an image with this method, the result is not the expected one.

Trying to get an image with this code (or any other existing imageID):

{"jsonrpc":"2.0",
 "method":"configuration.export",
 "params":{
    "options": {
         "images": ["156"]
      }, 
      "format": "json"
  },
  "auth":"2847454aaa55a9abf354db9ded233e49",
  "id":1}

Will always return this:

{"jsonrpc":"2.0",
 "result":"{\"zabbix_export\":{\"version\":\"2.0\",\"date\":\"2014-11-05T16:15:59Z\"}}","id":1}

It looks like the method can not find the image with the imageID.

The other objects groups, hosts, maps, screens and templates work as expected.