Style COOI 2.5AND2

My earliest model has not been updated for a long time. This update brings optimization of the art style. Although this model is set at 1.5, I recommend starting with 768*1024*2. This model is very suitable for creating large-scale scenes. An important characteristic of all my models is that they have rich backgrounds. For creating complicated images, it is recommended to use ddim  50 steps for sampling.