Instagram
First thing I have to say the Instagram app is that it, like Pinterest, is better when on a computer or a larger screen than a smartphone.
I definitely think that Instagram is a preferred choice to flickr for libraries sharing their photographs. Instagram is easier to organize, allows tags and feeds photos from most recent to oldest (whereas flickr feeds oldest to newest).
SnapChat
I added Shapchat to my phone about two years ago. Like most picture apps, it has a lot of potential for creatively and creating art. Like this guy makes:
More of Game than a Picture App
However Snapchat isn’t like any other picture app. Any potential user needs to understand that it isn’t a photo edit app (allow the pictures taken can be altered in some ways). Nor is Snapchat a means of storing pictures. Instead its more like a game. A user takes a picture, and sends it. When the picture is received it’s only visible for a few seconds. Then its gone. For some this is an annoying trait, for others it simply add to the fun.
Finding Friends
When I first started with Snapchat I remember I had really hard time finding friends. It took me a long time to locate any of my friends on Snapchat because I could search for them by their name, or email or find them through my other social medias. Instead I had to know their precise snapchat user name.
Privacy issues
Like all social media sites SnapChat has had some bad PR on its (lack of) privacy settings. Privacy settings can be set, but it can be difficult to do it. There has also been controversy in whether the ‘view once’ pictures really disappear or if there are merely “hidden”. And if they are merely “hidden” who is accessing them.