>>8193341
With ChaiNNer you would do it like picrel.
If the image is above 1280x720, downscale to 1280x720 first.
Maybe even downscale to 480p if it's 540p or something.
To get the frame you want to upscale, I usually just use ShareX through my MPC-HC video player at native resolution.
Here's the upscaled frames in the workflow, both using Ani4K+ESRGAN aswell as ESRGAN by itself: https://slow.pics/c/e76su5V0?canvas-mode=fit-height&image-fit=contain