Helper - captioning images

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:bookmark: This guide explains how to enable and configure AI powered image captions, which is part of the Helper feature of Discourse AI plugin.

:person_raising_hand: Required user level: Administrator

Image captioning allows users to harness AI to caption any uploaded image, providing detailed descriptions. Users can manually trigger captioning by clicking the Caption with AI button that appears on images in the composer.

Features

  • Manual Caption with AI button on images in the composer
  • Editable caption with ā€œ(Captioned by AI)ā€ attribution

Enabling Image Caption

Prerequisites

You must configure at least one vision-powered Large Language Model (LLM) from a provider.

To get started you can configure them through the Discourse AI - Large Language Model (LLM) settings page.

Configuration

  1. Go to Admin ā†’ Plugins
  2. Search for discourse-ai and ensure itā€™s enabled
  3. Ensure the Helper feature is enabled by checking ai helper enabled
  4. In ai helper enabled features ensure image_caption is added ā€” note that it is not included by default
  5. Select the agent at ai helper image caption agent
  6. Ensure the desired user groups are included in composer ai helper allowed groups so they can use the caption button

Technical FAQs

Why is the caption description not matching the image?

  • This depends on the vision-powered LLM and the image itself. More powerful LLMs might be able to better describe the picture but that is dependendent on the model. Picture fidelity and the subject of the picture are also important factors to consider in caption output.

Last edited by @sam 2026-03-20T06:03:12Z

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When an image is uploaded, a short summary (about 1 sentence) is given. I assume that is generated by AI and will incur costs?

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Yes you would incur a cost and that would depend on the provider

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@NateDhaliwal, this should help give you some rough estimates.

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Right, thanks!

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One very important instruction is missing here, took me a long time to figure it out:

The list of AI helper enabled features does not by default include ā€œImage captionā€, so I had to add that one specifically:

The image shows a screenshot of a black interface with an input field containing the text "image_caption" with red underlines and a search bar labeled ā€œimage_captionā€ (Captioned by AI)
The image shows a screenshot of a black interface with an input field containing the text "image_caption" with red underlines and a search bar labeled ā€œimage_captionā€ (Captioned by AI)408Ɨ224 4.43 KB

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Found (and fixed) one more problem: if you set ā€œAI auto image caption allowed groupsā€ to the ā€œeveryoneā€ group it will not automatically caption anything for anyone (regardless of the userā€™s setting) I had to explicitly set it to include all trust levels.

The image shows a screen displaying options for enabling AI auto image captioning, allowing users to toggle trust levels for this feature. (Captioned by AI)

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Everyone is a bit problematic, because it isnā€™t real group, amd it includes anons, who canā€™t write and upload anything.

But on my forum trust_level_0 works just fine including everybody who are logged in.

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I think the op needs an update

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I really liked it :frowning:

I was confused why it stopped working, but now I at least know why.