HiDPI splash screen variants ignored if set via manifest.mf

A DESCRIPTION OF THE PROBLEM :
SplashScreen class javadoc claims HiDPI scaled image is supported and can be set via manifest.mf file or via `-splash` command-line parameter.
While the selection of the correct scale of splash screen works for the `-splash` command-line parameter, it does not work if the same setting is set in manifest.mf.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
In my scenario, I created these images: splash.png, splash@125pct.png, splash@150pct.png, splash@2x.png and put them in `img` directory. Then I build a .jar file, ensuring there is this line in the manifest.mf file: `SplashScreen-Image: img/splash.png`.
See included project on GitHub.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Splash screen properly scaled on my 4K resolution.
ACTUAL -
Splash screen rendered at default 1.0 scale.

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https://github.com/PoloShock/splash-screen-bug
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CUSTOMER SUBMITTED WORKAROUND :
Using the `-splash:` command-line parameter targeting directory with a same content works as expected.

FREQUENCY : always