The official High Resolution Texture Pack for Sleeping Dogs was originally released as a free DLC for the of the game. If you are looking for this for a non-Steam version, the availability depends on which version of the game you own. 1. Identify Your Game Version
If you cannot find the official pack for your version, the modding community has created high-definition overhaul mods that often surpass the original official pack in quality. original (2012) version The official High Resolution Texture
Do not verify file integrity through GOG/Epic after installing. The launcher may delete the HD files, thinking they are "corrupt." Simply play the game. original (2012) version The official High Resolution Texture