[Bug]: Enabling inverted sorting destroys the preview image

[PurpleSmurf2]

Preflight Checklist

• I have searched the issue tracker for a bug report that matches the one I want to file, without success.

OpenComic Version

1.6.6

Operating System

Linux Mint 22.3 Cinnamon based on Ubuntu 24.04.3

Installed via

flatpak

Steps to reproduce

1. Open a comic collection with comics in it
2. Activate “inverted” when sorting & Grid View
3. Comics sorting is inverted correctly but the preview image is broken.

Expected Behavior

Preview Image shows always the first image of a file.

Actual Behavior

The preview image is inverted too.

Error message

No response

Additional Information

It shows the last page of a comic instead of the first page as preview image. I don't think this is intended.

Sample file

No response

[ollm]

I've changed it to use reading order instead of browsing order for thumbnail/poster generation cca841e

Build: https://mega.nz/file/rPYgQK7Y#MtipDXdip6iDO7Sec-vGLfGcuD7rca4GVKQxVFdhEUM