Append function example

gistfile1.txt

{
    "application_id":"YOUR_APP_ID",
    "src":"http://placekitten.com/420/540",
    "functions":[
        {
            "name":"append",
            "params":{
            "other_images":"http://placekitten.com/220/540",
                "vertical":false
            },
            "save":{
                "image_identifier":"foo"
            }
        }
    ]
}