The image processing function of CS does not rely on any cloud server. If the picture is large or the number of pictures is large, the app may use a lot of mobile phone memory to process.
If the phone has less memory or the phone's CPU performance is not running well, the app may be stuck.
There are several ways to optimize your phone's performance:
1. Close some unused apps from the background
2. Delete some unwanted photos or videos
3. Delete the cache of video & shopping apps
4. Restart the phone