The primary image, in the case of multi-image sources, may not
necessarily be the first image.
Test images produced with patched version of enc-heif that
allowed overriding the primary image. The correct primary
image is green, while the other image is red.
Pick-to: 6.10
Change-Id: Iba26b13fdb4898d7babc5fb173ad38b16f864e80
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>