1 Introduction  
2 Pre-trained Generative Adversarial Networks  
2.1 Preliminary  
2.2 Large-scale GAN models  
3 Analyzing and Understanding Large-scale GAN Models  
3.1 Neuron Understanding  
3.2 GAN Inversion  
3.3 Semantic Disentanglement and Discovery  
4 Applications to Image Editing and Restoration  
4.1 Image Editing  
4.2 Image Restoration  
4.3 Other Applications  
5 Discussion  
5.1 Challenges and Open Problems  
5.2 Conclusion