Update (Resolved)
The link condition works correctly — my issue was due to tag restrictions limited to certain categories.
Additionally, I found that both Oneboxes and image links trigger both the link and image conditions.
I’d like to request a way to distinguish uploaded images from image links, so that image tags only trigger for uploads.
This distinction matters because some plugins (such as Topic List Previews) only generate preview thumbnails for uploaded images — not for external image links.