Update README.md

Author: vadimkantorov

README.md

@@ -15,8 +15,8 @@ If you use this code, please cite our work:
 
 Source | 3 | 15 | 50
 --- | --- | --- | ---
-**mpegflow** | ![]() | ![]() | ![]()
-Ground truth | ![]() | ![]() | ![]()
+**mpegflow** | ![](https://raw.githubusercontent.com/vadimkantorov/mpegflow/master/examples/mpi_sintel_final_alley_1_vis_hue_examples/000003.png) | ![](https://raw.githubusercontent.com/vadimkantorov/mpegflow/master/examples/mpi_sintel_final_alley_1_vis_hue_examples/000015.png) | ![](https://raw.githubusercontent.com/vadimkantorov/mpegflow/master/examples/mpi_sintel_final_alley_1_vis_hue_examples/000050.png)
+Ground truth | ![](https://raw.githubusercontent.com/vadimkantorov/mpegflow/master/examples/mpi_sintel_final_alley_1_vis_hue_examples/gt_frame_0002.png) | ![](https://raw.githubusercontent.com/vadimkantorov/mpegflow/master/examples/mpi_sintel_final_alley_1_vis_hue_examples/gt_frame_0014.png) | ![](https://raw.githubusercontent.com/vadimkantorov/mpegflow/master/examples/mpi_sintel_final_alley_1_vis_hue_examples/gt_frame_0049.png)
 
 # mpegflow
 The tool accepts a video file path as command-line argument and writes MPEG-flow (motion vectors) to standard output. By default, the tool outputs the motion vectors arranged in two matrices - dx and dy.