PhotoCloud Frame Slideshow may remember your username/password for services which do not support security tokens (for example Samba and OwnCloud). PhotoCloud never sends your data anywhere else but the stream server itself, solely for the purpose of authenticating and downloading images. Images are downloaded to your phone only, they are never uploaded anywhere. The images are cached for quicker display, you can delete the caches at any time.
PhotoCloud uploads warning and error messages anonymously to Crashlytic, for the sole purpose of helping bug fixing. Those error messages never contain any username nor password. Other than that, PhotoCloud uploads nothing nowhere else, except for the sole purpose of downloading images (you have to let the server know that you wish to download given image) :-D
The user data is not read by PhotoCloud in any way. PhotoCloud does not ask for user name, password nor anything else except for an access token, which is used by PhotoCloud to read your files (Google Drive) or photos (Google Photos). Only read-only access is used; PhotoCloud will not modify nor append any data nor photos.