@Brown Wolf, no one can tell you for sure if an app is fake based on an image - and in my opinion you have two choices to minimize the risk. The first is to visit the official site (https://bluewallet.io/) and from there click on their official PlayStore link, and the second is to also visit their official Github link from the same source and download the app from there.

As far as I know, there is no way to verify their files before installation.