CustomImageView: Fixed crash when the image URL is not valid

matrixConsole/View/CustomImageView.m

@@ -473,6 +473,13 @@
 }
 
 - (void)updateProgressUI:(NSDictionary*)downloadStatsDict {
+
+    // Sanity check: updateProgressUI may be called while there is no stats available
+    // This happens when the download failed at the very beginning.
+    if (nil == downloadStatsDict) {
+        return;
+    }
+
     NSNumber* progressNumber = [downloadStatsDict valueForKey:kMediaLoaderProgressRateKey];
     
     if (progressNumber) {