It's an img2img work. The original picture is a photo of a Gundam Aerial*(from Anime Mobile Suit Gundam: the Witch from Mercury) plastic model.
An easy way to make mecha musume designs.

masterpiece, best quality,Amazing,beautiful,detailed,concept art,design art,1girl,solo,(Clear face),(Clear eyes),Science Fiction,military,leotard
Negative prompt: lowres, bad anatomy, bad hands, text, error, missing fingers, extra digit, fewer digits, cropped, worst quality, low quality, normal quality, jpeg artifacts, signature, watermark, username, blurry
Steps: 28, Sampler: Euler a, CFG scale: 12, Seed: 763051600, Size: 512x640, Model hash: e6e8e1fc, Denoising strength: 0.75, Eta: 0.67, Clip skip: 2, ENSD: 31337, Mask blur: 4