WILD (in-the-Wild Image Linkage Dataset): This dataset was created in collaboration with PoliMi, UniTn, La Sapienza, and UniCt. It consists of a closed set of 10,000 images from a mix of 10 commercial and open-source text-to-image generators, and an open set of another 10,000 images from 10 open-source generators of different nature. Thanks to an automatic prompt writing mechanism, the head-and-shoulder images are balanced with respect to sources and characteristics of the portrayed imaginary people. This dataset is a challenging benchmark which allows to benchmark synthetic image source attribution models in closed set attribution, open-set attribution, and robust attribution. The latter task is enabled by the post-processed replicas of test set and validation set images, and of half of the open set images. Each of these images has one copy with a single post-processing step, one with two steps, and one with three steps.