imagesize.js

Determines the size of an image without reading or downloading it entirely.

Implemented using an incremental parser, and can be fed multiple times with data chunks of any size.

Usage

var imagesize = require('imagesize');

imagesize(stream, function (err, result) {
  if (!err) {
    console.log(result); // {type, width, height}
  }
});

The first argument should be a stream emitting data and end events.

Full example:

var http = require('http');
var imagesize = require('imagesize');

var request = http.get('http://nodejs.org/images/logo-light.png', function (response) {
  imagesize(response, function (err, result) {
    // do something with result

    // we don't need more data
    request.abort();
  });
});

Advanced usage:

You can also use the incremental parser directly:

var Parser = require('imagesize').Parser;
var parser = Parser();

switch (parser.parse(buffer)) {
  case Parser.EOF:
    // needs moar data
    break;
  case Parser.INVALID:
    // invalid input, abort
    break;
  case Parser.DONE:
    var result = parser.getResult();
    break;
}