An open-source, web-based 'multi-up' viewer that supports zoom-pan-rotate functionality, ability to display/compare simple images, and images with annotations.
Manifest hosting institution: University Library Heidelberg
Observed behavior
Description: Moiré pattern not from iiif server (cantaloupe with bicubic filter, but without gamma correction), but from mirador asking for 512 px² tiles and scaling them in browser - perhaps to get a smooth zooming experience.
Screenshots / screen recordings / GIFs
(Screenshot from Firefox, rotated by 90° clockwise)
Observed behavior
(Screenshot from Firefox, rotated by 90° clockwise)
Image is the same as https://digi.ub.uni-heidelberg.de/diglit/mod_kunst1888/0063 (presentation without adequate image processing, too; JPGs with gamma correction and filtering)