Hello,
Looks like you use Android app.
There are several ways:
1. You can upload image logo in web platform in template. Image should be 500x500px
Then in mobile app choose Image tile->in design tab choose default option->return to devices->you should see this logo in app
2. In app->Choose Image tile->in design tab choose custom option->choose some template icon->return to devices->you should see this icon in app
3. In app->Choose Image tile->in design tab choose custom option->add image->add URL link with your image->return to devices->you should see this image in app
and also it was some bug in
this will be fixed in next app version
Regards