AI icon generator: app icon art at 1024 × 1024 from a prompt

An AI icon generator turns a prompt into a square image of one simple symbol, which you then resize, cut out if it needs a transparent background, and finish for the place the icon goes. Ask for one centered symbol with no text on a plain background, and several options per call. On Sume, ChatGPT Image 2.5 takes an exact 1024 × 1024, the layout size Apple lists for iOS, iPadOS and macOS app icons. The result is a PNG, JPEG or WebP, not an SVG, and Apple's app icons are layered, so treat the generated image as starting artwork, not the finished icon file.

Icon sizes and design guidance come from Apple's App icons guidelines and Google's Play Console help on preview assets. Sume facts come from the Image API docs and the Sume API reference. All were read on 2026-09-28.

What size should an app icon image be?

Generate at the size the platform lists, or at a whole multiple of it when that size is too small for the model. Apple says the system automatically scales your icon to produce the smaller variants shown in places like Settings and notifications, so one large square is the starting point.

ChatGPT Image 2.5 takes an exact custom image_size with both edges in multiples of 16 and 655,360 to 8,294,400 pixels in total. 512 × 512 is under that minimum, so generate at twice the size and scale it down in an image editor. Image Upscale 1.0 can't shrink an image: its factor runs from 1 to 4.

How do I write a prompt for an app icon?

Apple's guidelines read like a prompt checklist. Turn them into words the model sees:

• One simple idea. Apple says to embrace simplicity in your icon design.
• No words. Apple says to include text only when it's essential to your experience or brand.
• An illustration, not a photo. Apple prefers illustrations to photos.
• Square, full-bleed and centered, with no rounded corners. Apple asks for square, unmasked layers for iOS, iPadOS and macOS, and the system applies the rounded corners itself.
• No drop shadows, glows or bevels. Apple says the system applies visual effects to icon layers, so there's no need to include them.
• Several options at once: the current catalog allows n up to 4 on ChatGPT Image 2.5. Game-item icons follow the same pattern: one object, centered, on a plain background.
• A 202 instead of 200 means the images are still being made: poll GET /v1/jobs/{id}/status, then read GET /v1/jobs/{id}/result.

curl -X POST https://api.sume.com/v1/images \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "openai/gpt-image-2.5",
    "prompt": "App icon: a paper plane made of two overlapping solid shapes, centered, flat colors on a plain deep blue square background, no text, no rounded corners, no shadow",
    "image_size": { "width": 1024, "height": 1024 },
    "n": 4,
    "output_format": "png"
  }'

Can I use the AI image as my iOS app icon?

As a starting point. Apple says you can provide a flattened image, but layers give you the most control: iOS, iPadOS, macOS and watchOS icons are assembled from layers in Icon Composer, a design tool included with Xcode. For those layers Apple prefers vector graphics, and PNG for raster artwork. Sume's image models return PNG, JPEG or WebP, not SVG, so use the PNG as a flattened icon or a raster layer, or redraw the symbol as a vector.

If you want the symbol apart from its background, cut it out: POST /v1/rmbg-1.0/remove returns a PNG with alpha, at $0.0225 per image on API pricing, plus a 5.5% agent fee by default. Apple asks that an imported background layer be full-bleed and opaque. For Google Play, the listing icon is a separate asset: Google says it doesn't replace your app's launcher icon.

How much does it cost, and what are the limits?

Each image is priced per model. ChatGPT Image 2.5 estimates each request's price from its size and quality, so read usage.cost in the response: it is the USD amount billed. Failed generations are not billed.

• No SVG and no layered file: the output is one flat PNG, JPEG or WebP image.
• The exact sizes here rely on ChatGPT Image 2.5's documented custom-size rules; other models list their own ratios and sizes in GET /v1/images/models.
• Scaling down is your step, in any image editor.
• A matching set means sending one finished icon as a reference for the next. Nothing guarantees the set stays consistent, so compare them side by side.
• Result URLs are signed, so download the icons you keep, and check each store's current requirements before you submit.