Customizer: Image height set incorrectly under current header when a cropped header image is set

[CreativeInfusion]

Using the Customizer select add new image and choose a header image from the media library. When prompted choose to crop it.

The Customizer then sets the height of the new image under 'Current header' to be very tiny.

Selecting another image and reselecting the new one restores normality.

Note that it works normally if you choose not to crop.

[valendesigns]

This is a duplicate of #31970

[CreativeInfusion]

I don't think it is talking about exactly the same problem.

31970 seems to be live previewing another theme and the cropped image is large and distorted.

This one is referring to the thumbnail of the cropped header image having a height set that is way too small - that's the thumbnail on the left hand side in the Customizer under the heading 'Current header'. The height is actually set on the container that the image is injected into using javascript.