attr function in jquery

attr function in jquery

its my code for editing image src with output from json request everything
works before return but when i'm write code to return output its getting
error, dont changing image src.
$(function(){
$( ".plimg" ).attr(
"src",
function( index ){
track = '212';
artist = 'azealea banks';
$.getJSON("http://ws.audioscrobbler.com/2.0/?method=track.search",
{
track: track,
artist: artist,
api_key: "ca86a16ce762065a423e20381ccfcdf0",
format: "json",
lang: "en",
limit: 1 },
function(data) {
var output = data.results.trackmatches.track.image[0]["#text"];
});
return output;
}
);
});