Reducing the size of the iOS installation package is something that many large and medium-sized apps have to do. Generally, they will start with resource files, compress pictures/audio and get rid of unnecessary resources. After optimizing these resources, we can also try to slim down the executable files. The larger the project, the larger the capacity of the executable file. Moreover, because APPStore encrypts executable files, the compression rate of executable files is low. The compressed executable files account for about 80%~90% of the entire APP installation package, which is still worth optimizing.