diff --git a/RNVectorIconsManager/RNVectorIconsManager.m b/RNVectorIconsManager/RNVectorIconsManager.m
index 88cfcba..a060074 100644
--- a/RNVectorIconsManager/RNVectorIconsManager.m
+++ b/RNVectorIconsManager/RNVectorIconsManager.m
@@ -40,7 +40,10 @@ RCT_EXPORT_METHOD(getImageForFont:(NSString*)fontName withGlyph:(NSString*)glyph
     UIGraphicsEndImageContext();
   
     NSData *imageData = UIImagePNGRepresentation(iconImage);
-    [imageData writeToFile:filePath atomically:YES];
+    BOOL success = [imageData writeToFile:filePath atomically:YES];
+    if(!success) {
+      return callback(@[@"Failed to write rendered icon image"]);
+    }
   }
   callback(@[[NSNull null], filePath]);
 
diff --git a/lib/create-icon-set.js b/lib/create-icon-set.js
index d8cd354..88c07c1 100644
--- a/lib/create-icon-set.js
+++ b/lib/create-icon-set.js
@@ -81,7 +81,7 @@ function createIconSet(glyphMap, fontFamily) {
 
   var imageSourceCache = {};
 
-  var getImageSource = function(name, size, callback) {
+  var getImageSource = function(name, size) {
     invariant(RNVectorIconsManager, 'RNVectorIconsManager not available, did you add the library to your project and link with libRNVectorIcons.a?');
 
     var glyph = glyphMap[name] || '?';
@@ -93,34 +93,23 @@ function createIconSet(glyphMap, fontFamily) {
     var cacheKey = glyph + ':' + size;
 
     return new Promise((resolve, reject) => {
-      if(imageSourceCache[cacheKey]) {
-        return resolve({ uri: imageSourceCache[cacheKey] });
+      var cached = imageSourceCache[cacheKey];
+      if(typeof cached !== 'undefined') {
+        if(!cached) { return reject(); }
+        return resolve({ uri: cached });
       }
       RNVectorIconsManager.getImageForFont(fontFamily, glyph, size, function(err, image) {
-        var result;
+        imageSourceCache[cacheKey] = image || false;
         if(!err && image) {
-          imageSourceCache[cacheKey] = image;
-          result = { uri: image };
-        }
-        callback && callback(err, result);
-        if (err) {
-          reject(err);
-        } else {
-          resolve(result);
+          return resolve({ uri: image });
         }
+        reject();
       });
     });
   };
 
 
   var TabBarItem = React.createClass({
-    getInitialState: function() {
-      return {
-        icon: false,
-        selectedIcon: false,
-      };
-    },
-
     componentDidMount: function() {
       var size = this.props.iconSize || TAB_BAR_ICON_SIZE;
       if(this.props.iconName) {