The go-to solution for efficient display of (very) large images with zooming capability is to use tile pyramids. It is the principle behind every map viewer (google maps, apple plans, leaflet etc.).
Our use case was to give our users the ability to view and add markers on building floor plans, with sufficient precision (hence a good zooming ability) and with good performance (network and interactions) in order to be usable on site.
This talk is a walk through the decision to start from scratch instead of using a third party native library.
Co-Founder at a tech company based in La Rochelle, on the atlantic coast of France. We work hard to bring an all-in-one solution for construction professionals.