HEIC image dimensions reported wrong for HEIC files with multiple images embedded

[grasdk]

A bug in pigallery due to a bug in a dependency: image-size/image-size#403:

HEIC files can contain multiple images. The image-size library only reports the dimensions of one of these images, not necessarliy the right one. In the case of this bug, the dimensions of a 512x512 image is reported on a much larger image:

Opening the issue here, so everyone knows that the bug is known. Originally reported as part of the issue posted by @malavolti in #877 (comment)_:

Image to recreate the problem: