This is a SD1.5 model trained on pop arts made by the one and only Roy Lichtenstein (And some other pop arts).
The model can only really do portraits, and even then, to get decent looking results, you do have to tinker with the prompt/create more samples.
Occasionally, it still makes realistic looking people with pop art background. For the time being, the best thing you can do is to simply adjust the prompt and/or rerun it.
There are definitely a lot of things I can do to improve the model, but I haven't got around to doing that.
To reference the art style, use the token: roypop style
You can check out the diffuser model here on huggingface
There is already an existing model that uses textual inversion. This is trained using Dreambooth instead, whether or not this method is better, I will let you judge.