Add an app for resizing images. Still needs rate limiting, and still trying to decide how to pass the correct URL to the app.

lib/roles/storage/plugins/image/task/transform.js

@@ -0,0 +1,26 @@
+var gm = require('gm')
+var Promise = require('bluebird')
+
+module.exports = function(stream, options) {
+  return new Promise(function(resolve, reject) {
+    var transform = gm(stream)
+
+    if (options.gravity) {
+      transform.gravity(options.gravity)
+    }
+
+    if (options.crop) {
+      transform.geometry(options.crop.width, options.crop.height, '^')
+      transform.crop(options.crop.width, options.crop.height, 0, 0)
+    }
+
+    transform.stream(function(err, stdout) {
+      if (err) {
+        reject(err)
+      }
+      else {
+        resolve(stdout)
+      }
+    })
+  })
+}