Post screenshot photo on facebook

Hi Guys, First I working in android platform with Facebook SDK. All I want is to post the image into facebook timeline, I saw the way how FB.Feed working, it's just taking the url image to post the link. But I have a different method I want to share my photo(screenshot taken inside the application) directly into Facebook with Hastag name like #Contest, #Complaints, #Goal, etc... I searched and they said I have to do this in one way which mean I can save my photo into some link with FB.API and use FB.Feed to call the link. But am confused actually I want to share my screenshot into facebook timeline, I want the way to do it. So far I used this unity scripts to share the image but it's not working.

 public void Share()
     {
         if(!ShareImage)
         {
             StartCoroutine(ShareImageShot());
         }
     }
 
     IEnumerator ShareImageShot()
     {
         ShareImage = true;
 
         yield return new WaitForEndOfFrame();
         Texture2D screenTexture = new Texture2D(Screen.width, Screen.height, TextureFormat.RGB24, true);
         
         screenTexture.ReadPixels(new Rect(0f, 0f, Screen.width, Screen.height),0,0);
         
         screenTexture.Apply();
         
         byte[] dataToSave = screenTexture.EncodeToPNG();
         
         string destination = Path.Combine(Application.persistentDataPath, Screenshot_Name);
         
         File.WriteAllBytes(destination, dataToSave);
         
         var wwwForm = new WWWForm();
         wwwForm.AddBinaryData("image", dataToSave, "InteractiveConsole.png");
         
         FB.API("me/photos", Facebook.HttpMethod.POST, Callback, wwwForm);
 
     }
 
     private Texture2D lastResponseTexture;
     private string lastResponse = "";
     private string ApiQuery = "";
     void Callback(FBResult result)
     {
         lastResponseTexture = null;
         if (result.Error != null)
             lastResponse = "Error Response:\n" + result.Error;
         else if (!ApiQuery.Contains("/picture"))
             lastResponse = "Success Response:\n" + result.Text;
         else
         {
             lastResponseTexture = result.Texture;
             lastResponse = "Success Response:\n";
         }
     }

There is no error, but when I press the share button nothing happened. please give me the correct way to do this.