1. In a digital media environment to facilitate management of image collections using at least one computing device, a method to automatically generate image captions using weak supervision data comprising: obtaining, by the at least one computing device, a target image for caption analysis; applying, by the at least one computing device, feature extraction to the target image to generate global concepts corresponding to the image; comparing, by the at least one computing device, the target image to images from a source of weakly annotated images to identify visually similar images; building, by the at least one computing device, a collection of keywords for the target image indicative of image details by extracting the keywords from the visually similar images; and supplying, by the at least one computing device, the collection of keywords indicative of image details as the weak supervision data for caption generation along with the global concepts.
9. The method of claim 1 , wherein caption generation includes multiple iterations to determine a sequence of words to combine as the caption for the target image and supplying the collection of keywords comprises providing the same keywords for each of the multiple iterations.