The International Image Interoperability Framework (IIIF) has become a widely accepted standard for the digital delivery of digital visual art and historical documents. Unfortunately, however, practice shows that the standard has some serious shortcomings that make it difficult to use in the field of art and culture. I will highlight these shortcomings and show how they could be addressed using the example of an open source IIIF-compliant high-performance image server (SIPI) developed for the Data and Service Center for the Humanities (DaSCH).