AngularJS with Web API: uploading files

Good day,

I have beed following at tutorial on how to upload files using angularjs using WebAPI from this link http://ift.tt/1bf54Lg It has been quite helpful,

In the tutorial there are four method

Task<IEnumerable<PhotoViewModel>> Get();
Task<PhotoActionResult> Delete(string fileName);
Task<IEnumerable<PhotoViewModel>> Add(HttpRequestMessage request);
bool FileExists(string fileName);

Now i need another method to get image by the image name, i have been trying with no result

//Task<PhotoActionResult> GetById(string fileName);

Please i need help on how to get file by id working

Thanks.