AI Image Editing Prompts Tested: Replace, Relight, and Preserve Identity

The short answer

Good AI image editing prompts are not miniature art directions. They are change contracts: name the supplied image as the source of truth, list what must stay fixed, describe one permitted change, and forbid the most costly forms of drift.

We tested that structure on September 3, 2026 with two fixed reference images and three edit jobs: replace only a portrait background, relight only the portrait, and change only a bottle's material while preserving its exact label. The same prompt and reference went to Nano Banana Pro, GPT Image 2, and Midjourney V8.2.

The scale is intentionally simple: 1 = failed the edit, 3 = usable with material caveats, 5 = followed the requested change while protecting the important invariants. These are visual editorial scores for the nine displayed outputs, not success rates or permanent model grades.

For a generation-only control, see the same-prompt three-model test. Editing is harder because a good output must satisfy the new brief and avoid breaking the source.

Method and reproducibility

The completed evidence run is 20260903t075235z-514b0ccedd; its manifest hash is 514b0cceddd25b65aff20462573dae0f5b7e19a2f0efcdd37c60c10f591783f7. Nine of nine planned display assets completed.

These are the two fixed, fictional references. The portrait hash is 3f5e68146bca7f0bd44be8e4bebb5b366b30890c989306fd52a600dfe082f162; the product hash is 38ca351b8d248ba8c204eb10ff68585a053fec59071d11595cf8186528409533.

One provider event needs disclosure. The first Midjourney relighting task reached a verified terminal failure with an explicit zero cost and produced no candidate image. The runner archived that receipt, then made one audited resubmission; the image below is the first URL from that resubmission. This was not a quality reroll. Separately, the Midjourney background asset was recovered from its already accepted task after a local fetch failed interruption, without another submission.

Midjourney responses exposed four candidate URLs and the runner automatically used the first; the other routes exposed one. Because the run includes different serving mechanics, a resumed download, and one terminal cost-zero retry, latency and operational reliability are excluded from the scores and ranking.

The prompt pattern: preserve, change, prohibit

Every tested prompt follows the same three-part contract:

1. Preserve — enumerate identity, geometry, crop, text, material-independent shape, and other invariants.
2. Change only — permit one background, lighting, or material transformation.
3. Do not — block beautification, extra props, new text, face reshaping, or any other likely shortcut.

The order matters. Put the reference authority and invariants before the new look, so the model does not treat the uploaded image as loose inspiration. The complete prompt-engineering guide explains the same idea for generation; the consistent-character guide goes deeper on identity anchors.

Premium Industrial Product Diagram

Nano Banana Pro

Prompt▾

{
  "reference": {
    "type": "image",
    "usage": "Use the uploaded image as the sole source of truth. Do not assume product category in advance."
  },
  "scene": {
    "description": "Minimal, premium product presentation layout inspired by high-end industrial design and product documentation.",
    "background": "Pure white, clean, distraction-free"
  },
  "layout": {
    "top_left": {
      "content": "Brand name",
      "style": "Modern sans-serif typography, subtle, elegant"
    },
    "left_column": {
      "content": "Multiple auxiliary product views",
      "views": ["Primary front or main view", "Secondary side view", "Alternate angle or rear view", "Detail or top view if applicable"],
      "arrangement": "Vertically stacked, evenly spaced, aligned"
    },
    "right_section": {
      "content": "Main hero product render",
      "style": "Large, dominant, photorealistic",
      "lighting": "Soft studio lighting",
      "materials": "Visually accurate to the uploaded product"
    }
  },
  "visual_style": {
    "aesthetic": "Scandinavian, modern, industrial documentation",
    "mood": "Calm, precise, professional",
    "color_palette": "Neutral and restrained"
  },
  "rendering": {
    "quality": "Ultra-high resolution",
    "shadows": "Soft and realistic",
    "accuracy": "Exact proportions and geometry fidelity"
  }
}

Copy

A real gallery edit prompt that declares the uploaded product the sole source of truth before describing the new presentation.Open in LocalBanana

Test 1: replace only the portrait background

Exact prompt

Edit the supplied portrait reference. Preserve the adult subject's exact identity, face shape, skin texture, expression, gaze, hair, charcoal knit top, body proportions, crop, and camera perspective. Replace only the plain background with a softly out-of-focus pale sage plaster wall and a single diffused window-shadow shape. Keep the existing neutral daylight direction and realistic edge detail around the hair. Do not beautify, change age, alter facial features, add jewelry, add text, add logos, or introduce another person.

Nano Banana Pro and GPT Image both do the boring thing—and for editing, boring is praise. The face shape, eye spacing, expression, straight shoulder-length hair, charcoal top, body scale, and front-facing crop remain close to the source. Each adds a pale sage wall and one soft window-shadow shape without turning the hair edge into a cutout.

The Midjourney result is an attractive portrait, but not a surgical edit. The hair becomes fuller and wavier, facial proportions move, skin is beautified, and the crop tightens substantially. It solves “make a portrait against a sage wall” while failing the more important instruction: keep this exact person and framing.

Nano Banana Pro

One Image Generates 9 Different Shots

Nano Banana Pro

Controlled Gaze Under Dominant Flash

Nano Banana Pro

Elves in the Snowscape

Test 2: relight without rebuilding the person

Exact prompt

Relight the supplied portrait reference as a natural late-afternoon window portrait while preserving the adult subject's exact identity, expression, gaze, hairstyle, charcoal knit top, background geometry, body proportions, crop, and camera perspective. Introduce warm directional light from camera left, a soft cool fill from camera right, realistic catchlights, protected skin highlights, and believable shadow transitions. Change lighting and color response only. Do not smooth the skin, reshape the face, change clothing, add objects, add text, add logos, or introduce another person.

GPT Image delivers the most literal lighting-only edit. The reference face, relaxed mouth, gaze, hairline, garment, body scale, and crop remain close, while warm light enters from frame left and a cooler, quieter side remains on frame right. The background geometry is nearly untouched.

Nano Banana Pro keeps the person and framing well enough for a strong result, but interprets “natural late-afternoon” as a harder beam with a sharper split across the face and torso. It is still recognizably an edit of the reference, hence 4/5 rather than a failure.

Midjourney produces handsome late-day light, but rebuilds the subject: the face narrows and changes, the hair is pulled back, the crop moves much closer, and less of the original body framing survives. Lighting quality cannot compensate for identity loss when the assignment says “change lighting only.” The score applies to the displayed retry output, not to the earlier cost-zero task failure.

Indie Sleaze Cool Girl Flash Portrait

Nano Banana Pro

Prompt▾

{
  "portrait_prompt": {
    "subject": "Based on <User Portrait>, a young woman with voluminous, messy, long hair, wearing a black sporty crop top with white trim and matching black shorts, white calf-high socks. She is sitting perched on a high dark wooden counter or piano top. Her pose is casual and edgy, leaning forward with one hand resting near her mouth, biting her finger slightly, gazing directly at the camera with a sultry, nonchalant expression. A silver bracelet on her wrist. Background includes a white wall with vintage posters taped up and brown wooden blinds. Foreground details include the neck of an electric guitar, a glass jar of cookies, and liquor bottles",
    "composition": "Full body shot, 35mm focal length, slightly low angle to emphasize leg length, sharp focus on subject with hard flash fall-off, messy but balanced framing",
    "camera_angle": "Eye-level relative to the seated subject, slightly low angle from the floor, medium distance",
    "lighting": "Direct on-camera flash photography, hard lighting creating a sharp drop shadow on the wall behind the subject, high contrast, reminiscent of 90s point-and-shoot aesthetics, no diffusion",
    "color_palette": "Vintage film aesthetic, Kodak Gold 200 simulation, warm tones from wooden blinds and furniture contrasted with cool white flash light, deep blacks, slightly grainy texture, lo-fi indie vibe",
    "mood": "Indie sleaze, candid, rebellious, cool girl aesthetic, raw and authentic, Y2K retro fashion editorial, snapshot style",
    "negative_prompt": "soft lighting, studio lighting, bokeh, professional studio portrait, airbrushed skin, 3d render, cartoon, illustration, distorted hands, missing guitar strings, floating objects, anatomical errors, stiff pose, over-processed, HDR"
  }
}

Copy

A gallery prompt with a supplied portrait slot and reusable scene logic—the source image owns the person, while the prompt owns the treatment.Open in LocalBanana

Orange Sunglasses Selective Color Portrait

Nano Banana Pro

Prompt▾

A studio-style close-up editorial portrait of a person with strong, well-defined facial features and slightly imperfect, natural skin texture. The subject wears a black tailored turtleneck with sharp, clean lines, layered under a high-collared black jacket in a minimalist contemporary fashion style.

The subject wears semi-transparent orange acetate sunglasses — rectangular frames with softly rounded edges, glossy finish, and amber gradient lenses — serving as the only colored element in the image.

Color concept: selective color photography — monochrome black-and-white image with only the sunglasses in vivid orange.

Mood is calm and confident, serious expression, direct gaze into the camera.

Lighting is soft frontal studio light with gentle shadows, even skin tones, cinematic contrast, and visible natural skin texture. Shot on a professional portrait camera, f/2.0, ISO 100, 1/125s. High resolution, ultra-sharp focus on the face.

Style: editorial luxury fashion portrait, photorealistic, professional studio photography, no illustration, no painterly effects.

Copy

A conditional gallery task where one element keeps its colour and everything else changes. Good edits make the invariant just as explicit as the transformation.Open in LocalBanana

For more precise light vocabulary, use the lighting-keyword guide and camera-settings prompt guide.

Test 3: change material while preserving exact packaging text

Exact prompt

Edit the supplied fictional hand-cream pack shot. Change only the amber bottle material to translucent frosted sage-green glass while preserving the bottle silhouette, black pump, white label shape, centered composition, camera angle, shadows, background, and photographic realism. The label must still read exactly "MORI", "HAND CREAM", and "50 ML" with the same spelling, capitalization, order, and clean black lettering. Do not add any other readable text, logo, symbol, prop, hand, or brand mark.

Nano Banana Pro executes the whole contract most cleanly: amber becomes translucent frosted sage green; the silhouette, black pump, white label, centered pack-shot logic, and background stay close; MORI, HAND CREAM, and 50 ML remain exact.

GPT Image also changes the bottle to frosted sage green and preserves all three lines exactly. Its bottle and rendering shift slightly more from the source, so it lands at 4/5, but it is a usable commercial edit after ordinary visual QA.

Midjourney delivers the most revealing miss. It preserves every requested word—MORI, HAND CREAM, and 50 ML—yet the bottle remains amber-brown. The backdrop turns sage and the product is restaged instead. This is why a text-perfect image can still fail an edit: the changed pixels are in the wrong place.

Nano Banana Pro

Stickers of Different Clothing Styles

Nano Banana Pro

Premium 3x3 Grid Studio Product Storyboard

A reusable AI image editing prompt template

Copy this structure, then replace every bracketed slot with something visible and testable:

Edit the supplied [portrait/product/scene] reference. Treat it as the source of truth.

PRESERVE EXACTLY:
- [identity, facial geometry, expression, hair]
- [object silhouette, label shape, readable text]
- [crop, camera angle, perspective, background geometry]

CHANGE ONLY:
- [one background, lighting, material, colour, or wardrobe variable]
- [where the change begins and ends]

ACCEPTANCE CHECK:
- [exact required text, count, colour, direction, or material]

DO NOT:
- [beautify, reshape, recrop, add props, add text, add logos, alter untouched regions]

The template works because it gives the edit a boundary. “Make it better” offers no way to distinguish improvement from damage; “change only the amber glass” does. For larger visual sequences, use the same invariant/variable split from the multi-panel guide.

What to inspect before shipping

Do not stop when the requested change appears. Compare the output against the source in this order:

1. Identity or product geometry — face shape, hairline, silhouette, pump, label bounds.
2. Crop and perspective — a closer portrait is not the same edit, even when the face looks plausible.
3. Untouched regions — background during a relight, clothing during a face edit, text during a material swap.
4. Exact text — spelling, capitalization, punctuation, line order, and extra copy.
5. The requested change — did the model alter the correct pixels, or merely recolour the surroundings?

The last check catches the Midjourney bottle result: a sage scene is not a sage bottle. The first two catch both Midjourney portrait results. A disciplined review is more valuable than another paragraph of flattering adjectives.

For model selection beyond these three edits, use the current AI image generator comparison, then browse Nano Banana prompts, GPT Image prompts, or Midjourney prompts to study real task shapes before running your own reference in LocalBanana.

FAQ

What is the best way to write an AI image editing prompt?

Name the supplied image as the source of truth, list every invariant, permit one change, define a visible acceptance check, and end with explicit prohibitions. “Preserve X; change only Y; do not alter Z” is more reliable than a long description of the desired mood.

Which model was best for AI image editing in this test?

There was no universal winner. Nano Banana Pro and GPT Image tied on background replacement; GPT Image led the relighting task; Nano Banana Pro led the material-and-label edit. Midjourney scored lower on all three displayed outputs because it changed identity or failed to change the requested material. Those findings apply only to this dated, single-run set.

How do I preserve a face while changing the background or lighting?

Put identity first and make it concrete: face shape, expression, gaze, hair, skin texture, clothing, proportions, crop, and perspective. Then say “replace only the background” or “change lighting and colour response only,” and forbid beautification, face reshaping, recropping, and new accessories.

How do I keep product-label text exact during an edit?

Quote every required line, state spelling, capitalization, and order, and forbid any other readable text. Check the words and the actual requested transformation separately. In this run, one result preserved the complete label but failed the material edit.

Was the Midjourney retry cherry-picking?

No. The first relighting task ended in a verified terminal failure with explicit zero cost and no candidate output. One audited resubmission was allowed, and its first returned URL became the displayed result. We exclude latency and reliability from the comparison because that exceptional path is not equivalent to the other jobs.