Hires fix improvements

[tazlin]

Currently hires fix runs an initial image job at the number of input steps. If the user requests 30 steps, the worker generates a 30 step image latent with the resolution of the smallest side pinned to 512 (and the longer side, if the sizes don't match, is set so the aspect ratio is respected). The worker then runs that image latent using the same number of steps (e.g., 30 as in this example) at the final resolution.

Some thoughts on improvements:

• The starting resolution and ending resolution could be API input options.
• The hires steps could/should be separate, and probably should default to a small fraction of the input steps.
• An option could be included to do non-latent upscales (which is to say, use a upscale model like ESRGAN) as in this comfy example.

[spinagon]

Or this https://gist.github.com/laksjdjf/487a28ceda7f0853094933d2e138e3c6

Update: this is now built into ComfyUI as PatchModelAddDownscale node
comfyanonymous/ComfyUI@bd07ad1