Hi there,
I ran into an issue when updating the Mint theme from the official Git repo.
Environment
- Discourse version:
3.6.0.beta3-latest(tests-passed) - Theme source: https://github.com/discourse/discourse-mint-theme (default branch)
- Installed via
/admin/customize/themes→ “Install” → “From a git repository URL”
Issue
When I click “Update to latest” for the Mint theme in the admin UI (/admin/customize/themes), the update fails with this error dialog:
The theme screenshots must be in one of the following formats: .jpg, .jpeg, .gif, .png. The screenshot light.webp has an invalid format.
In about.json, the theme currently references:
"screenshots": [
"screenshots/light.webp",
"screenshots/dark.webp"
]
However, according to the Discourse theme docs, theme screenshots are only allowed to be jpg, jpeg, gif, or png, so .webp gets rejected by the core validation.
Steps to reproduce
- Install the Mint theme from the official Git repo in /admin/customize/themes.
- Go to the Mint theme entry.
- Click “Update to latest” .
- Observe the error dialog about light.webp having an invalid format.
Proposed fix
I opened a PR that converts the screenshots to PNG and updates about.json accordingly:
- screenshots/light.webp → screenshots/light.png
- screenshots/dark.webp → screenshots/dark.png
- about.json updated to:
"screenshots": [
"screenshots/light.png",
"screenshots/dark.png"
]
With this change, the theme updates cleanly in the admin UI and the screenshots display correctly.
Happy to adjust the PR if there is a preferred way to handle screenshots (or if .webp is meant to be supported by core in the future).