Steps to replicate the issue (include links if applicable):
Create a page with the following content:
[[File:Thumbup.jpg|thumb|50px|''thumb'']]
- See https://en.wikipedia.org/w/index.php?title=User:Jonesey95/sandbox&oldid=1152044871 for an example
What happens?:
Linter reports "thumb" as a bogus image option.
What should have happened instead?:
"thumb" in italics should be allowed as a valid image caption. No Linter error should be detected.
Software version (skip for WMF-hosted wikis like Wikipedia):
Other information (browser name/version, screenshots, etc.):
This was reported in https://phabricator.wikimedia.org/T179605#4956758 but it should have been opened as a separate bug.