[TIMOB-13436] Refresh cache for imageloader if the underlaying local file changed.

__TESTING INSTRUCTION__

Use the following [code](https://gist.github.com/srahim/5407896) in your app.js
__Make sure to include image files with `.JPG` extension in the resources folder of your app.

Click on the coverflow image to update the image with the current timestamp. Make sure the image new image does not get cropped.