11. A computer usable program product comprising one or more computer-readable storage devices, and computer usable code stored on at least one of the one or more storage devices, the stored computer usable code comprising: program instructions to extract, using a processor and a memory to perform Natural Language Processing (NLP) on a comment to a social media post, an entity that is referenced in the comment, the entity being an object other than a human face that is depicted in an image in the post; program instructions to analyze the image to determine whether the entity is represented in the image; program instructions to compute, responsive to the entity being represented in the image, a sentiment value of the comment relative to the entity; program instructions to assign, to a characteristic of a graphical artifact, a value corresponding to the sentiment value; program instructions to determine a position relative to an area occupied by the entity in the image; program instructions to cause the graphical artifact to be overlaid on the image at the position and with the value of the characteristic; program instructions to determine that a set of comments references the entity, the set including the comment; program instructions to compute a second sentiment value of a second comment in the set of comments; and program instructions to combine the sentiment value with the second sentiment value to form an overall sentiment value; and program instructions to use the overall sentiment value as the sentiment value in the program instructions to assign.
11. A computer usable program product comprising one or more computer-readable storage devices, and computer usable code stored on at least one of the one or more storage devices, the stored computer usable code comprising: program instructions to extract, using a processor and a memory to perform Natural Language Processing (NLP) on a comment to a social media post, an entity that is referenced in the comment, the entity being an object other than a human face that is depicted in an image in the post; program instructions to analyze the image to determine whether the entity is represented in the image; program instructions to compute, responsive to the entity being represented in the image, a sentiment value of the comment relative to the entity; program instructions to assign, to a characteristic of a graphical artifact, a value corresponding to the sentiment value; program instructions to determine a position relative to an area occupied by the entity in the image; program instructions to cause the graphical artifact to be overlaid on the image at the position and with the value of the characteristic; program instructions to determine that a set of comments references the entity, the set including the comment; program instructions to compute a second sentiment value of a second comment in the set of comments; and program instructions to combine the sentiment value with the second sentiment value to form an overall sentiment value; and program instructions to use the overall sentiment value as the sentiment value in the program instructions to assign. 18. The computer usable program product of claim 11 , wherein the computer usable code is stored in a computer readable storage device in a server data processing system, and wherein the computer usable code is downloaded from the server data processing system over a network to a remote data processing system for use in a computer readable storage device associated with the remote data processing system.