Apps to help with memory

[Mum2three]

My mother has Alzheimer's and as a consequence has lost nearly all her ability to communicate. A friend mentioned that she had heard of an app which has old photographs of objects from the past and old scenes for use as a talking point and to help trigger memory - only she can't remember what it is called. I have tried searching on Google but can't seem to find anything relevant - has anyone heard of any such apps? Any suggestions would be much appreciated as it did sound like it would be worth a look. Many thanks.