Technologies are generally described for methods and systems effective to generate an alert through sentiment analysis. In some examples, a device may receive initial image data, where the initial image data may be associated with an initial image. The device may further detect sentiment values in the initial image data, where the sentiment values may correspond to two or more locations in the initial image. The device may further compare respective sentiment values with an sentiment threshold in order to identify region data in the initial image data that satisfies the sentiment threshold. The device may further generate the alert based on the identification of the first region data.