Stable Diffusionは512x512px以上で使う
japanese high school girl in uniform with waist-length black hair, blue eyes. japanese anime style. full shot. 
512x512 / 256x256
ドキュメントに512より小さくすると低品質になるとかいてある
>Going below 512 might result in lower quality images.
> Going over 512 in both directions will repeat image areas (global coherence is lost).
global cohernceって何？
> The best way to create non-square images is to use 512 in one dimension, and a value larger than that in the other one.
なぜ？
モデルが512x512でfine tuningされてるから
>The Stable-Diffusion-v-1-4 checkpoint was initialized with the weights of the Stable-Diffusion-v-1-2
> checkpoint and subsequently fine-tuned on 225k steps at resolution 512x512 on "laion-aesthetics v2 5+" and 10% dropping of the text-conditioning to improve classifier-free guidance sampling.
もしかして小さいと小さい画像（アイコン）のようなものから学習したりするんだろうか？と思ったけどそう言うことではないのかな