In the digital age, social media platforms have become the primary avenue for cities to promote themselves, attracting tourists and stimulating economic growth. Cities including Shanghai and New York are typical examples of this trend, leveraging social media to showcase their unique offerings. Nevertheless, comprehension of how these promotional videos resonate with potential visitors and what images they project to the audience remains a critical challenge. This study attempts to address this issue by utilising an approach that combines natural language processing (NLP) and corpus analysis techniques. We analysed the comments associated with promotional videos of both Shanghai and New York, focusing on their linguistic features and cultural nuances. Through a comparative analysis of comments data, this research seeks to identify similarities and differences in the cities’ images shaped by these promotional efforts across distinctive cultural contexts (the eastern Shanghai and the western New York). Our results have shown that both Shanghai and New York are perceived as desirable global cities of tourism and urban life. However, Shanghai's image is more strongly tied to its national identity and role within Asia, while New York emphasises its global influence and themes of opportunity and dreams. Accordingly, this research has employed computational methods to investigate textual representations within comments, offering insights into the complex interplay between social media, city branding and public perception. Furthermore, this proposed poster will contribute to future explorations in social computation and social media research by providing an analytical framework through this case study.