Resources used: (bare in mind that I do quite a lot of editing on pictures so you might not get quite the same results)

Photoshop
Stable Diffusion (Forge Flux) 
Model:  yiffymix_v62Noobxl

Prompt Infos: 

Red Hedghog: 

Steps: 35, Sampler: Euler a, Schedule type: Automatic, CFG scale: 7, Seed: 991253897, Size: 1024x1024, Model hash: 5246f81705, Model: yiffymix_v62Noobxl, Denoising strength: 0.3, Clip skip: 2, Mask blur: 4, Inpaint area: Only masked, Masked area padding: 32, Lora hashes: "StS-Illustrious-Detail-Slider-v1.0: 2e7a68ec7e2e, Lady_Maria_of_The_Astral_Clocktower_-_Bloodborne: d481f84fd53e"

masterpiece, best quality, amazing quality, male, very aesthetic, high resolution, absurdres, <lora:StS-Illustrious-Detail-Slider-v1.0:3>, <lora:Lady_Maria_of_The_Astral_Clocktower_-_Bloodborne:1>
sonic the hedgehog \(series\), male, red Hedgehog, standing, tricorne, gloves, hat feather, ascot, cape, male, gray and red clothes, orange eyes, looking at viewer, simple dark background, solo, black boots, brown pants,

Negative prompt: realism, 3D,busty, ugly face, mutated hands, low res, blurry face, black and white, text, human, watermark, chubby, pubic hair, eyelashes, lips, eyelashes

Purple Echidna: 

Steps: 35, Sampler: Euler a, Schedule type: Automatic, CFG scale: 7, Seed: 967318334, Size: 1536x1536, Model hash: 5246f81705, Model: yiffymix_v62Noobxl, Denoising strength: 0.3, Clip skip: 2, Mask blur: 4, Inpaint area: Only masked, Masked area padding: 32, Lora hashes: "StS-Illustrious-Detail-Slider-v1.0: 2e7a68ec7e2e, Lady_Maria_of_The_Astral_Clocktower_-_Bloodborne: d481f84fd53e"

masterpiece, best quality, amazing quality, male, very aesthetic, high resolution, absurdres, <lora:StS-Illustrious-Detail-Slider-v1.0:3>, <lora:Lady_Maria_of_The_Astral_Clocktower_-_Bloodborne:1>
sonic the hedgehog \(series\), male, purple echidna, standing, tricorne, gloves, hat feather, ascot, cape, female, gray and black clothes, purple eyes, looking at viewer, simple dark background, solo, black boots, pants, breasts, purple fur,

Negative prompt: realism, 3D,busty, ugly face, mutated hands, low res, blurry face, black and white, text, human, watermark, chubby, pubic hair, eyelashes, lips, eyelashes, tooth, skirt, ((bulge)),


Background changes in SwarmUI: (After cutting them out and merging them in Photoshop)

{
"sui_image_params": {
"prompt": "Replace the blue background behind two Sonic-style anthropomorphic characters (a red male and a purple female, both dressed in dark Victorian hunter outfits with capes and feathered tricorn hats) with the interior of a gothic castle. The scene should feature grand architecture, tall windows, and shafts of light streaming through, casting moody rays onto a foggy stone floor. Keep the characters fully intact, in their current pose, lighting, and clothing.",
"model": "FLUX_Kontext_Dev",
"seed": 1362374195,
"steps": 40,
"cfgscale": 1.0,
"aspectratio": "Custom",
"width": 1536,
"height": 1536,
"sampler": "euler_ancestral",
"fluxguidancescale": 1.0,
"initimagecreativity": 1.0,
"maskblur": 4,
"automaticvae": true,
"negativeprompt": "",
"swarm_version": "0.9.6.3"
},
"sui_extra_data": {
"date": "2025-06-29",
"initimage_filename": "Duo switch.png",
"initimage_resolution": "1536x1536",
"prep_time": "0.24 sec",
"generation_time": "3.33 min"
},
"sui_models": [
{
"name": "FLUX_Kontext_Dev.safetensors",
"param": "model",
"hash": "0x75bda215f4febf4a7024d23a4c18d09f99c3ce745f8ecec8faa5e68c2c4fa8aa"
}
]
}