  Lossy compression introduces complex compression artifacts, particularly the
blocking artifacts, ringing effects and blurring. Existing algorithms either
focus on removing blocking artifacts and produce blurred output, or restores
sharpened images that are accompanied with ringing effects. Inspired by the
deep convolutional networks (DCN) on super-resolution, we formulate a compact
and efficient network for seamless attenuation of different compression
artifacts. We also demonstrate that a deeper model can be effectively trained
with the features learned in a shallow network. Following a similar "easy to
hard" idea, we systematically investigate several practical transfer settings
and show the effectiveness of transfer learning in low-level vision problems.
Our method shows superior performance than the state-of-the-arts both on the
benchmark datasets and the real-world use case (i.e. Twitter). In addition, we
show that our method can be applied as pre-processing to facilitate other
low-level vision routines when they take compressed images as input.
