What decides the size of the logo displayed on the Spotlight?

[Kyouma 48]

I thought the size would be determined by the resolution of the logo, but that seems not to be the case.

I have 4 examples. 

Link Click 800x310

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Bleach 800x310

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Clevatess 2400x772

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Jaadugar 1200x637

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Even though Clevatess and Jaadugar have a higher resolution, the other 2 appear a lot bigger. Why is that?

I'm currently in the process of changing the art for all my shows, but I'm unsure what resolution I should pick to have the correct size. 

Because while Clevatess has a good size, Link Click and Bleach are too big and Jaadugar is a bit small for my liking, even though the resolution would suggest it to be different. 

Any insights would be appreciated.

Don't know if this is specific to Apple TV or a general one.