Interesting Microsoft Teams Background Image requirement

Can Microsoft clarify, what this Microsoft Teams Background Image requirement means - "Aspect ratio: greater than 4"?

For, if Aspect Ratio is two values - H/V, then it is not understandable, what value is mentioned.

But, if Aspect Ratio is one value - result of dividing H by V, then it is confusing, because images listed in %appdata%\Microsoft\Teams\Backgrounds\Uploads are not images where H is 4 times more than V (or even more).