If you mean very long, unusual, or decorated fingernails, there isn’t a special name for the person. They would simply be described as someone with long nails, extreme nail art, or elaborate manicures.
Depending on the style, people might say:
- Nail artist — someone who creates decorative nail designs (if they do it professionally)
- Nail enthusiast — someone who enjoys growing or decorating their nails
- Acrylic/gel nail wearer — if the nails are artificial extensions
If you’re referring to a specific picture or a particular nail style, describe it and I can help identify the look.