Remove gm dependency and update tests.

lib/resize.js

@@ -1,10 +1,33 @@
 import debugname from 'debug';
 const debug = debugname('hostr-api:resize');
-import gm from 'gm';
+import lwip from 'lwip';
+import imageType from 'image-type';
+
+const supported = ['jpg', 'png', 'gif'];
 
 export default function(input, size) {
   debug('Resizing');
-  const image = gm(input);
 
-  return image.resize(size.width, size.height, '>').stream();
+  const type = imageType(input);
+
+  if (!type.ext || supported.indexOf(type.ext) < 0) {
+    throw new Error('Not a supported image.');
+  }
+
+  return new Promise((resolve, reject) => {
+    lwip.open(input, type.ext, (errIn, image) => {
+      if (errIn) {
+        return reject(errIn);
+      }
+      image.cover(size.width, size.height, (errOut, resized) => {
+        if (errOut) {
+          return reject(errOut);
+        }
+
+        resized.toBuffer(type.ext, (errBuf, buffer) => {
+          resolve(buffer);
+        });
+      });
+    });
+  });
 }