imgix APIs
Rendering API
Fill Generative Prompt

Fill Generative Prompt


Premium Feature

Fill Generative Prompt is currently available for imgix customers on a Premium plan. If you’re interested in this feature, please contact our sales team (opens in a new tab) to get more information on this feature.

Provides a text suggestion to the output of fit=fill&fill=gen. It accepts URL-safe string values but can also be base64 encoded (fill-gen-prompt64). The shorthand version of this parameter can also be used (fill-gen-prompt).

Generative fill with no prompt: Original image of a man standing on a cliff,format&w=600&h=900&fill=gen&fit=fill

Generative fill using fill-gen-prompt=eagle%20flying%20around:

Cropped image using generative fill,format

Prefer Base64 Variant

imgix recommends using the Base64 variant version of this parameter to make encoding values easier.


Guarantee of keyword output

While fill-gen-prompt suggests what the output generative fill should look like, it does not guarantee that the prompt keywords will be used in the final fill.

For example, we regenerated the image using an identical prompt but with a different seed value, but it contained none of the prompt keywords (eagle flying around):

Fill generative image missing an eagle,format&fit=fill&w=600&h=900&auto=compress&fill-gen-seed=1&fill-gen-prompt=eagle%20flying%20around&fill=gen

Character limits

There is no direct character limit for prompt values, though we recommend keeping your image URLs under 1024 characters.