🖼️ Topic Gallery

Canapin · February 2, 2026, 2:27pm


	Summary	Add a gallery view for each topic
	Preview	Click to see a gallery example
	Repository Link	https://github.com/Canapin/discourse-topic-gallery
	Install Guide	How to install plugins in Discourse

Description

Topic Gallery displays all images from a discussion on a dedicated page.

Use cases

Ideal for image-focused communities and/or categories in which users post many pictures.
It allows for a full picture experience without the regular topic interface and other contents getting in the way.

Mobile view:

You can try it here. This is primarily a test instance, so the availability is not guaranteed.

Features

Main features

Infinite swiping! ^[1]
User and date filters
Starts gallery from a given post
Group-specific access
Category-based exclusions
Link to the source post below the currently open image, so you’re never lost:
Shows grouped pictures (belonging to the same post) on mouse over:

Navigation from a topic to a gallery

Several buttons are available to navigate from a Topic to a Gallery:

Below the timeline:

Topic Gallery timeline button290×174 2.26 KB
At the end of a topic:
On each post (can be disabled in the settings):

If you open the gallery from a post, the gallery is filtered and only shows images starting from this post. You can cancel this filter with a single click:

Gallery URLs

The gallery URL syntax is the same as a regular topic, but /t/ is replaced with /gallery/:

https://canapin.discourse.diy/t/share-your-pictures/10

https://canapin.discourse.diy/gallery/share-your-pictures/10

There’s also a public JSON endpoint:
https://canapin.discourse.diy/gallery/share-your-pictures/10.json

Security & queries

Feature access is restricted to allowed groups and in allowed categories.
Galleries are restricted to users with access to their source topic.

Uploads queries exclude:

Non-user-uploaded images
Non-post references (custom emojis, avatars, etc.)
Uploads from posts that the current user has no access to, meaning:
- Whispers (if the current user can’t see whispers)
- Hidden posts
- Deleted posts
- Ignored users’ posts

Gallery Behavior

Hotlinked images are not shown.
Small images are not shown (minimum resolution can be changed in settings).
Duplicate images are shown once.
Images inside quotes are shown.
Images in spoilers or any other block that alters their visibility, are shown.

Settings

Name	Type	Default	Description
`topic_gallery_enabled`	boolean	`true`	Enable the topic gallery plugin.
`topic_gallery_allowed_groups`	group_list	`admins`	Groups that are allowed to access the topic gallery.
`topic_gallery_minimum_image_size`	integer (0–1000)	`64`	Minimum width and height (in pixels) for images to appear in the gallery. Images smaller than this in either dimension are excluded.
`topic_gallery_excluded_categories`	category_list	`""`	Categories where the topic gallery is disabled. Topics in these categories will not show gallery buttons or the gallery page.
`topic_gallery_post_menu_button`	boolean	`true`	Show a gallery button inside each post.

By default, the plugin is enabled for admins only. Visit settings to enable other groups.

Reaching the end of the first batch of images automatically loads and appends the next batch. ↩︎

Canapin · February 16, 2026, 12:40pm

I finally released this plugin

You can see a preview here: Gallery - Share your pictures! - Canapin

MarkoK · February 16, 2026, 1:02pm

This is such a cool idea and implementation.
Will try this later but is there a way to add image description that would show on the image popup below image?

NateDhaliwal · February 16, 2026, 1:30pm

I think you can use alt text:

![Some alt text here](upload://...)

You can also click on the above image to see the alt text.

Canapin · February 16, 2026, 1:55pm

Ah, there’s an oversight from me. This plugin’s photoswipe configuration seems to show the original filename instead of the custom title. I’ll fix this

NateDhaliwal · February 16, 2026, 1:58pm

@Canapin Why not use the built-in Discourse lightbox()?

github.com/discourse/discourse

frontend/discourse/app/lib/lightbox.js

main

import { isRailsTesting, isTesting } from "discourse/lib/environment";
import { helperContext } from "discourse/lib/helpers";
import { SELECTORS } from "discourse/lib/lightbox/constants";
import quoteImage, {
  canBuildImageQuote,
} from "discourse/lib/lightbox/quote-image";
import { isDocumentRTL } from "discourse/lib/text-direction";
import { escapeExpression } from "discourse/lib/utilities";
import { i18n } from "discourse-i18n";

export default async function lightbox(elem, additionalData = {}) {
  if (!elem) {
    return;
  }

  const currentUser = helperContext()?.currentUser;
  const siteSettings = helperContext().siteSettings;
  const caps = helperContext().capabilities;

  const { default: PhotoSwipeLightbox } = await import("photoswipe/lightbox");

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Canapin · February 16, 2026, 2:08pm

Apparently, while I can use the built-in lightbox (that’s I was doing in the first versions of this plugin), I can’t configure and tweak it for my needs. Notably, I couldn’t have it interact with my methods for the infinite loading/swiping, so I had to ship my own.

Canapin · February 16, 2026, 2:59pm

I can’t fix this, unfortunately. Image titles are written in the posts’ content and aren’t stored in any table.

For performance reason, my queries don’t return the posts’ content, so I can’t parse it to retrieve the titles.

I guess I’ll leave the filenames then. Even tho this information is rarely valuable…
Non-modified filenames most of the time just reveal where the image comes from and nothing more.

For example in my test instance:

image.png → “image” filenames are images pasted directly in the composer
Gemini_Generated_Image_8h4wt58h4wt58h4w.jpg → Guess
ComfyUI-ExtraMD-Large_315126945425344_00000.jpg → Local AI image generator
the-tattooer-is-totally-right-v0-s2f8spm3l-D5908.jpg → Probably saved from a website
cropped-android-chrome-512x512-1-32x32.png → Smartphone screenshot

Etc.

Should I consider it as a sensitive information? Image names are used by default for titles when we upload them on Discourse. If we edit the titles, the original information is unavailable for users. Yet, this plugin discloses it.

Edit: Yeah, I should probably not display the original filename.

Re-edit: Fixed.

TheWalkingDead110 · February 16, 2026, 5:23pm

Gallery icon at the bottom of a topic on mobile is not designed well. (Does not follow other buttons shape/size). Looks fine on desktop. Thank you.

Canapin · February 16, 2026, 5:52pm

Before

After

Fixed, thanks for the report

TheWalkingDead110 · February 16, 2026, 5:57pm

Thank you! Would it also be possible to have a setting do disable the automatic “from post #123” when a user clicks on the gallery button mid-topic please? So basically the full gallery available no matter what specific gallery button you click.

Canapin · February 16, 2026, 6:00pm

You can disable the post buttons in the plugin’s setting. The remaining gallery buttons (timeline, and end of topic) open the gallery from the start.

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