Core Insights - The iPhone 4 has seen a resurgence in demand, increasing by 1000%, becoming a trendy product among young people due to its nostalgic appeal driven by TikTok creators [1][5] Group 1: Market Trends - The revival of the iPhone 4 is attributed to its unique photographic qualities, which are perceived as a nostalgic symbol, particularly its grainy texture that evokes a specific atmosphere [1][5] - This trend mirrors similar movements in domestic markets, such as the popularity of CCD trends and various film filter functionalities, all centered around a shared appreciation for nostalgia [1][5] Group 2: Technical Aspects - Technically, the iPhone 4 features a 5-megapixel camera, which significantly lags behind the current 48-megapixel imaging systems offered by Apple in terms of resolution and fidelity [4][7] - The grainy effect associated with the iPhone 4's photography is primarily a result of technical limitations rather than a desired feature, similar to the graininess found in film photography due to material defects [4][7] - While the iPhone 4 can produce the desired grainy effect, it is not recommended to use it as a primary device due to its outdated iOS 7 system, which poses significant security vulnerabilities [4][7]