android : deleting an image

Use the code below, it may help you.

File fdelete = new File(file_dj_path);
if (fdelete.exists()) {
    if (fdelete.delete()) {
        System.out.println("file Deleted :" + file_dj_path);
    } else {
        System.out.println("file not Deleted :" + file_dj_path);
    }
}

to refresh gallery after deleting image use below code for send Broadcast

(for < KITKAT API 14)

 sendBroadcast(new Intent(Intent.ACTION_MEDIA_MOUNTED,
 Uri.parse("file://" +  Environment.getExternalStorageDirectory())));

For >= KITKAT API 14 use below code

MediaScannerConnection.scanFile(this, new String[] { Environment.getExternalStorageDirectory().toString() }, null, new MediaScannerConnection.OnScanCompletedListener() {
            /*
             *   (non-Javadoc)
             * @see android.media.MediaScannerConnection.OnScanCompletedListener#onScanCompleted(java.lang.String, android.net.Uri)
             */
            public void onScanCompleted(String path, Uri uri) 
              {
                  Log.i("ExternalStorage", "Scanned " + path + ":");
                  Log.i("ExternalStorage", "-> uri=" + uri);
              }
            });

Because:

ACTION_MEDIA_MOUNTED

is deprecated in KITKAT(API 14).

EDITED 04-09-2015

its working fine check below code

public void deleteImage() {
        String file_dj_path = Environment.getExternalStorageDirectory() + "/ECP_Screenshots/abc.jpg";
        File fdelete = new File(file_dj_path);
        if (fdelete.exists()) {
            if (fdelete.delete()) {
                Log.e("-->", "file Deleted :" + file_dj_path);
                callBroadCast();
            } else {
                Log.e("-->", "file not Deleted :" + file_dj_path);
            }
        }
    }

    public void callBroadCast() {
        if (Build.VERSION.SDK_INT >= 14) {
            Log.e("-->", " >= 14");
            MediaScannerConnection.scanFile(this, new String[]{Environment.getExternalStorageDirectory().toString()}, null, new MediaScannerConnection.OnScanCompletedListener() {
                /*
                 *   (non-Javadoc)
                 * @see android.media.MediaScannerConnection.OnScanCompletedListener#onScanCompleted(java.lang.String, android.net.Uri)
                 */
                public void onScanCompleted(String path, Uri uri) {
                    Log.e("ExternalStorage", "Scanned " + path + ":");
                    Log.e("ExternalStorage", "-> uri=" + uri);
                }
            });
        } else {
            Log.e("-->", " < 14");
            sendBroadcast(new Intent(Intent.ACTION_MEDIA_MOUNTED,
                    Uri.parse("file://" + Environment.getExternalStorageDirectory())));
        }
    }

below is logs

09-04 14:27:11.085    8290-8290/com.example.sampleforwear E/-->﹕ file Deleted :/storage/emulated/0/ECP_Screenshots/abc.jpg
09-04 14:27:11.085    8290-8290/com.example.sampleforwear E/-->﹕ >= 14
09-04 14:27:11.152    8290-8290/com.example.sampleforwear E/﹕ appName=com.example.sampleforwear, acAppName=/system/bin/surfaceflinger
09-04 14:27:11.152    8290-8290/com.example.sampleforwear E/﹕ 0
09-04 14:27:15.249    8290-8302/com.example.sampleforwear E/ExternalStorage﹕ Scanned /storage/emulated/0:
09-04 14:27:15.249    8290-8302/com.example.sampleforwear E/ExternalStorage﹕ -> uri=content://media/external/file/2416