This is it . . . In one sense, it is a simple image viewing utility, supporting most common image file formats.
Catalogs can hold any number of image files.
Images can be added to catalogs either by rendering or importing. Scroll through all the images in a catalog, writing notes in for each image . It even supports simple compositing. Now use it to load up image sequences and preview them as animations. Only the cropped area will render, which can save rendering time.