We have a cute QNAP NAS (serves mounts, iTunes) and wireless network.
A tablet with a nice place to dock it and speakers would do the job. If we can get a couple of apps.
First up streaming music player. Skifta looks good. Already tried it on phone and easy setup. Simple interface to play music. Doesn't do photo slideshow, just allows photo browsing.
http://www.skifta.com/ Qualcomm. Cute slogan. "Skifta - May your stuff be with you."
Good philosophy. Also makes easy to stream music to a different device. https://play.google.com/store/apps/details?id=com.skifta.android.app&hl=en
I tried MediaHouse before on phone. It does the job also, plays music. Browses photos. Interface a bit clunkier but more options. https://play.google.com/store/apps/details?id=com.dbapp.android.mediahouse&hl=en
On the server side, some of my music files need to be cleaned up and metadata added :-7
Next. Digital Photo Frame.
https://play.google.com/store/apps/details?id=softick.android.photoframe&hl=en Photo Slides (Photo Frame) softick
Hmmm. Would like to play over wireless.
Need to search more for playing wireless and liking/selecting photos, making playlists etc.
We will also be able to play music from internet.
Pandora is a spotify clone? Or more? Or less?
https://play.google.com/store/apps/details?id=com.android.DroidLiveLite xiialive looks shiny
https://play.google.com/store/apps/details?id=com.leadapps.android.radio&hl=en AOR A Online Radio
And of course it being a tablet it can do a bit more fondleslabby wondrousness. Games, music/sound, youtube, internet, family calendar, Skype, ... oh dear.
Being an Android tablet we need to build a photo frame / music playing docking station. Humm. Wood? Sugru? :)