Capitalized versions of valid File options are usually ignored, but are not flagged as Linter bogus file options.
Here are some test cases that show the problem on en.WP:
[[Image:Milgrom Mordechai.jpg|Thumb|upright|link=foo| MOND was proposed by Mordehai Milgrom in 1983]]
[[Image:Milgrom Mordechai.jpg|Frame|upright|link=foo| MOND was proposed by Mordehai Milgrom in 1983]]
[[Image:Milgrom Mordechai.jpg|Border|thumb|upright|link=foo| MOND was proposed by Mordehai Milgrom in 1983]]
[[Image:Milgrom Mordechai.jpg|border|thumb|upright|link=foo| MOND was proposed by Mordehai Milgrom in 1983]]
[[Image:Milgrom Mordechai.jpg|Frameless|upright|link=foo| MOND was proposed by Mordehai Milgrom in 1983]]