AI banner generator for YouTube: a 2560×1440 channel banner

To make a YouTube banner with AI, generate a 16:9 image at the size YouTube recommends, 2560 × 1440 pixels, and keep text and logos inside YouTube's safe area. On Sume, ChatGPT Image 2.5 takes 2560 × 1440 as a custom image_size because that size meets its documented size rules, so you can ask for YouTube's size directly; describe the scene in the prompt and keep the important parts away from the edges, which YouTube crops on some devices.

YouTube's numbers are quoted from its Help page Manage your channel branding, which can change. Sume facts come from the Image API docs. Both were read on 2026-09-27.

What size is a YouTube banner?

YouTube shows the banner as a background at the top of your channel page. The same image is used on computer, mobile, and TV displays, but it shows differently on each device. YouTube's guidelines for it:

How do I generate a 2560 × 1440 banner with Sume?

Send the size as a custom image_size to openai/gpt-image-2.5 on POST /v1/images. It passes all four custom-size rules: both edges are multiples of 16, the long edge is under 3840, 16:9 is inside the 3:1 limit, and 3,686,400 pixels is inside the 655,360–8,294,400 range.

• High quality can run past the 30-second wait and return 202 with a job to poll instead of the image, so branch on the status code.
• Results are Sume-hosted, signed URLs in data[].url. Download the banner before you upload it to YouTube.
• YouTube's guidelines ask for 6 MB or smaller, so check the downloaded file's size. This example asks for jpeg; png and webp are the other options.

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": "Wide YouTube channel banner for a woodworking channel: a warm workshop with hand tools on a pegboard, soft morning light, open space across the middle for a title",
    "image_size": { "width": 2560, "height": 1440 },
    "quality": "high",
    "output_format": "jpeg"
  }'

Where should text and logos go on a YouTube banner?

Inside the safe area. YouTube gives it as 1235 × 338 pixels at the 2048 × 1152 minimum and says the image will get cropped on certain views and devices, so treat everything outside that area as background that may not show.

In YouTube Studio, the banner is set under Customization, then Profile, where you can select a preview and change the crop before you publish.

Generated lettering needs proofreading. For a channel name that must be exact, ask the model for empty space and add the words in an editor; AI image with text covers when to let the model letter it.

Can I use another model for a YouTube banner?

Yes, if you resize afterwards. Nano Banana 2 and Nano Banana Pro list 16:9 and a 4K resolution tier, but they take no custom pixel sizes: a pixel size maps to their nearest listed ratio, and the docs do not give the 4K tier's pixel dimensions. In current code, Sume only records a requested pixel size on these models and does not resize the file, so resize it to 2560 × 1440 in your own editor.

How much does an AI YouTube banner cost?

ChatGPT Image 2.5 estimates each request's price from its size and quality, and in current code its catalog price line is for a 1024 × 1024 image at high, so read the real figure from the response: usage.cost is the USD amount billed to your wallet. Billing is all-or-nothing, and a failed or canceled generation is not billed.