Caching Images?

I am developing a Food Recommendation Engine. We have a lot of photos开发者_高级运维 which has to be downloaded from the server during the usage of the Application.

Do we need to cache or store the images locally just to reduce the network activity ?

If the data from the server is not going to change then you should store them but if the data is changed then you can do two things

1. On the server keep a last updated data date and depending on that always fetch that date from server, check if the last updated data is not obsolete if yes then fetch again or there is no need
2. Second approach is Store as cache and fetch every time you start your app