Open Graph image size: 1200 × 630 and the 1.91:1 ratio

The Open Graph image size to use is 1200 × 630 pixels: Meta's sharing docs recommend images of at least that size so they display well on high-resolution devices, as close to a 1.91:1 aspect ratio as possible. The smallest allowed image is 200 × 200 pixels, and the file must not exceed 8 MB.

Meta's rules are quoted from its Sharing for Webmasters page Images in Link Shares; Sume facts come from the Image API docs and the Sume API reference. All were read on 2026-09-29. Other sites that read Open Graph tags publish their own guidance; this post quotes Meta's.

What are the og:image size requirements?

The og:image tag gives the URL of the image that appears when someone shares the page; Meta's docs describe it for shares to Facebook. Meta's numbers for that image:

Why doesn't my Open Graph image show the first time?

Meta's crawler scrapes and caches a page's metadata the first time the page is shared, and has to see an image once before it can render it, so the first share may show no image. Meta gives three fixes:

• Run the URL through the Sharing Debugger to pre-fetch the page's metadata.
• Force a scrape of the URL through the Graph API.
• Add the og:image:width and og:image:height tags, so the crawler can render the image immediately without downloading it first.

How do I change an Open Graph image?

Meta caches images by URL, so put the new image at a new URL, or the preview won't update. Keep the old image online, since existing posts may still reference it, and pre-cache the new one. Updating the image doesn't refresh the preview of old shares on its own.

How do I make an Open Graph image with AI?

ChatGPT Image 2.5 (openai/gpt-image-2.5) on Sume takes an exact custom image_size, but 1200 × 630 isn't one: both edges must be multiples of 16. Generate at 1920 × 1008 instead, a valid size with the same shape, then scale it down by 1.6 to 1200 × 630 in an image editor or your build step. Image Upscale 1.0 can't do that step: its factor runs from 1 to 4.

Add n to get several options in one call, up to the model's ceiling in the catalog; each image is billed. Results are signed, Sume-hosted URLs in data[].url, so copy the file into your site and point og:image at your own URL. Generating images per page from an AI coding tool is covered in Generate website images with Claude Code.

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 header illustration for a blog post about home composting: a wooden bin, green leaves, warm morning light, clear space on the left, no text",
    "image_size": { "width": 1920, "height": 1008 },
    "n": 2,
    "output_format": "jpeg"
  }'