How can I change the body type or size of models in my product images using AI?

Quick Answer

Use Nightjar to show your product on different body types by swapping the AI person in the shot, not by reshaping a single image. Pick a Fashion Model with the body you want from the 80+ pre-built roster, build a custom one from a few reference photos, or write a short Custom Directions note like "plus size" or "tall athletic" while the garment, color, and composition stay consistent.

Important caveat: Nightjar Fashion Models are reusable AI people for product photography and visual consistency, not body measurement, size recommendation, or fit prediction.

Why showing different body types matters

Shoppers ask, "Will this look good on me?" Showing one body type narrows the answer for most of your audience. Imagery that reflects a wider range of bodies builds trust and can help reduce returns driven by fit uncertainty, which is a recognised pain point in fashion ecommerce. The flip side is real: brands that have generated diverse imagery without underlying inventory or representation work have drawn public criticism, so the goal is honest variety, not a swap that misrepresents what you actually stock.

The problem with traditional approaches

• Photoshoots: Booking multiple models across body types is expensive and slow.
• Photoshop: Manually reshaping a body in a single image rarely looks believable and takes hours per asset.
• General AI tools: Prompt-only generators often redraw the whole image when the body changes, so the garment, fabric, and composition shift along with the person.

How Nightjar approaches body-type variation

Nightjar treats the on-figure person as a separate, reusable ingredient called a Fashion Model: an AI person you can pick, swap, or build from references and reuse across Generations. The garment in your product photo is anchored separately, so changing the Fashion Model leaves the product, lighting, and composition more stable than a prompt-only redo.

You have three paths, in order of control:

1. Swap to a different pre-built Fashion Model. Nightjar ships 80+ Fashion Models spanning age ranges and gender presentations, so you can choose a different body and rerun the same shot.
2. Build a custom Fashion Model from references. Upload 1 to 5 source photos of the body you want (with the right to use that likeness), then reuse that identity across the catalog.
3. Add a short note in Custom Directions. Custom Directions are user-written instructions layered on top of your selected ingredients. A clause like "plus size" or "tall athletic build" nudges the result without rewriting the whole brief.

To lock in the rest of the shot, save the Photography Style (the camera, lighting, and mood), Composition (framing, angle, and pose), background, and output settings as a Recipe: a saved Create-form setup you can reapply to the next product so each body-type variant starts from the same controls.

Starting without a Fashion Model image

You do not need an existing on-model photo. Upload a flat lay or ghost-mannequin shot, choose or create a Fashion Model with the body type you want, and Nightjar can generate the garment on that person. This is how brands build a more representative catalog without booking another shoot for every variant.

A practical caution: present these images as catalog options, not as a substitute for fit data or for hiring real people from the communities you serve. Fashion Models help preserve the look and direction of your shoot. They are not a fit-prediction tool.