Optimize image URLs

How to include your own images in API-generated gammas, and how to avoid common issues with broken or missing images.

You can include your own images in API-generated gammas by placing image URLs directly in your inputText (Generate API) or prompt (Create from Template API). This page covers the technical requirements and common pitfalls.

Quick reference

• URLs must be HTTPS, end with a recognized image extension, and be publicly accessible.

• Set imageOptions.source to noImages if you want only your provided images.

• Gamma fetches and re-hosts images during generation, so URLs only need to be live at generation time.

• Test URLs in an incognito window -- if you can see the image without logging in, Gamma can access it.

How it works

When Gamma encounters an image URL in your input, it:

1. Detects the URL based on format (see requirements below)

2. Fetches the image from your URL during generation

3. Re-hosts the image on Gamma's CDN

If the fetch fails for any reason, the image is silently skipped — you won't get an error, but the image won't appear in the output.

URL requirements

For Gamma to detect and use your image URLs, they must meet all of the following:

Requirement	Details
HTTPS only	URLs must start with https://. HTTP URLs are ignored.
Recognized image extension	Must end with one of: .jpg, .jpeg, .png, .gif, .webp, .svg, .heic, .heif, .avif
Publicly accessible	No authentication headers, login walls, or IP restrictions. Gamma's servers must be able to fetch the URL directly.

Query parameters are fine. URLs like https://cdn.example.com/photo.jpg?width=800&quality=90 will work — Gamma matches the extension before any ? query string.

What won't work

URL type	Why it fails
http://example.com/photo.jpg	Not HTTPS
https://example.com/image	No recognized extension
https://example.com/document.pdf	Not an image extension
https://internal.corp.net/photo.jpg	Not publicly accessible
<img src="https://example.com/photo.jpg">	HTML tags — use the raw URL instead
	Already-wrapped markdown is skipped by the preprocessor

Placement in your input

Image URLs can appear inline with your text or on their own line — both work. Gamma scans for any whitespace-separated URL matching the requirements above.

Inline with text

"inputText": "Our headquarters https://cdn.example.com/office.jpg is located in San Francisco."

On its own line

"inputText": "Our headquarters\nhttps://cdn.example.com/office.jpg\nis located in San Francisco."

Multiple images

"inputText": "Product lineup:\nhttps://cdn.example.com/product-a.jpg\nhttps://cdn.example.com/product-b.png\nhttps://cdn.example.com/product-c.webp"

Use noImages to prevent extra images

If you want only your provided images (no AI-generated or stock images added by Gamma), set imageOptions.source to noImages:

{
  "inputText": "...",
  "textMode": "preserve",
  "imageOptions": {
    "source": "noImages"
  }
}

Without this, Gamma may add additional images from the selected source alongside yours.

Hosting recommendations

Since Gamma fetches and re-hosts your images during generation, the URLs only need to be accessible at generation time. However, using reliable hosting avoids intermittent failures.

URL type	Recommended	Notes
Public CDN (Cloudflare, CloudFront, Fastly)	✅ Yes	Permanent, fast, reliable
Direct image hosting (Imgur, Unsplash)	✅ Yes	Generally permanent
S3/GCS signed URL (7+ day expiry)	✅ Yes	Works if expiration is long enough
S3/GCS signed URL (< 24 hours)	❌ No	May expire before Gamma fetches it
Google Drive / Dropbox share links	⚠️ Maybe	Can break if permissions change; not a direct image URL
URLs behind CDN hotlink protection	❌ No	Gamma's servers will be blocked
Localhost / private network IPs	❌ No	Not accessible to Gamma's servers

Quick test: Open your image URL in an incognito browser window. If you can see the image without logging in, Gamma can access it too.

Troubleshooting

Images appear during generation but disappear on refresh

Your URLs were accessible when Gamma first rendered the content, but the re-hosting step failed — usually because of hotlink protection, rate limiting, or signed URLs that expired between the initial render and the background upload. Use permanent, publicly accessible URLs.

Images don't appear at all

Check that your URLs meet all three requirements (HTTPS, recognized extension, publicly accessible). Also check that you're not wrapping them in HTML <img> tags or markdown image syntax — use raw URLs only.

Some images work, others don't

Each URL is fetched independently. A mix of working and broken images usually means some URLs have access restrictions or don't end with a recognized extension. Test each URL individually in an incognito window.

Related

• Generate from text for where image URLs fit in inputText

• Generate from template for using image URLs in the prompt field

• Poll for results for the generation workflow after submitting your request