When hotlinking images, it used to be possible to resize them using modifiers to the tag:
[img width={width} height={height} ...]{url}[/img]
This functionality is presently broken and I assume that the root issue is related to the {alt} error somehow. In the example below, I am attempting to resize the image from a height of 241 pixels to 500, but the tag has no effect.
[img height=500]https://www.bbcode.org/images/bbcode_reference.png[/img]
While https vs http works as a fix for getting an image to display properly, not having this functionality would mean that each and every image inserted into a post would have to be resized at its source.