It is not a site, well there are some sites used in the process but the majority of work goes on in Stability Matrix/Comfy UI and Photoshop. I have listed below a workflow from an older thread. I have made some tweaks to my own setup since then, but should be enough info to get you going:
My images are currently generated using Stability Matrix with WAI-illustrious-SDXL, SDXL VAE, HiResfix and Yolo for face & hands
I then do a lot of manual editing in Photoshop for clean up and backgrounds
I am currently using Comfy UI with Wan2.2 for animations (The "Wan 2.2 14B Image to Video" is a simple one to use but you need to relink a couple of nodes for it to work)
Then I use Ezgif to convert MOVs to GIFs
Then 8Upload for SFW images and Imgbox for NSFW ones