Adding music from itunes to slideshow in iphoto

After you subscribe to Apple Music, you will have a mixture of songs in your library - the songs you owned previously (songs you purchased from the iTunes Store, ripped from CDs, recorded as audio files from old vinyl records or the radio, or downloads from somewhere), plus the streamed songs from Apple Music. You will still be able to use the songs you previously imported to your iTunes Library for slideshows, in iMovie as sound tracks, or in GarageBand and Logic projects, but as Yer_Man explained, the Apple Music songs in your library will not be available for any kind of project that would save the song in a different format and remove the attached digital rights.

No. You can only use music that you own. You never own the tracks with Apple Music, only pay for access to them.