Image editor do not update custom image sizes when the main image is modified.

[Fab1en]

In the Media Library, images can be edited directly in WP : you can crop them, rotate and so on. You can also decide to apply changes to the main image only, the thumbnails only or to all sizes.
But even when applied to all sizes, only thumbnail, medium and large size are updated. Size added via add_image_size are not changed.

I thought this was a feature to implement, but when digging in the code, I saw that the custom image sizes are taken care of. There is just a small bug that prevents the sizes to be set correctly, hence the resizing process fails for those sizes.

I will submit a patch to correct this.

[Fab1en]

Proposed correction patch

[markoheijnen]

Duplicate of #19889.