  Versatile Video Coding (H.266/VVC) standard achieves better image quality
when keeping the same bits than any other conventional image codec, such as
BPG, JPEG, and etc. However, it is still attractive and challenging to improve
the image quality with high compression ratio on the basis of traditional
coding techniques. In this paper, we design the multi-scale grouped dense
network (MSGDN) to further reduce the compression artifacts by combining the
multi-scale and grouped dense block, which are integrated as the post-process
network of VVC intra coding. Besides, to improve the subjective quality of
compressed image, we also present a generative adversarial network (MSGDN-GAN)
by utilizing our MSGDN as generator. Across the extensive experiments on
validation set, our MSGDN trained by MSE losses yields the PSNR of 32.622 on
average with teams IMC at the bit-rate of 0.15 in Lowrate track. Moreover, our
MSGDN-GAN could achieve the better subjective performance.
