11. In a digital media environment to facilitate access to collections of images using one or more computing devices, a system comprising; one or more processing devices; one or more computer-readable media storing instructions executable via the one or more processing devices to implement a caption generator configured to perform operations to automatically generate image captions using word vector representations including: obtaining a target image for caption analysis; applying feature extraction to the target image to generate attributes corresponding to the image; supplying the attributes to the caption generator to initiate caption generation; outputting by the caption generator a word vector in a semantic word vector space indicative of semantic relationships between words in sentences formed as a combination of the attributes; and subsequently using the word vector in post-processing operations to generate a corresponding caption by: selecting a dictionary; and mapping the word vector to words in the semantic word vector space based on the selected dictionary.
11. In a digital media environment to facilitate access to collections of images using one or more computing devices, a system comprising; one or more processing devices; one or more computer-readable media storing instructions executable via the one or more processing devices to implement a caption generator configured to perform operations to automatically generate image captions using word vector representations including: obtaining a target image for caption analysis; applying feature extraction to the target image to generate attributes corresponding to the image; supplying the attributes to the caption generator to initiate caption generation; outputting by the caption generator a word vector in a semantic word vector space indicative of semantic relationships between words in sentences formed as a combination of the attributes; and subsequently using the word vector in post-processing operations to generate a corresponding caption by: selecting a dictionary; and mapping the word vector to words in the semantic word vector space based on the selected dictionary. 12. A system as recited in claim 11 , wherein outputting the word vector in the semantic word vector space enables changing of the selected dictionary for different contexts.