You do not mention what version of OS X you are using?
You need iDVD or Roxio Toast to render/author/burn a DVD that will be playable on any DVD player.
There is no other way to create a DVD that will play on any standard DVD player.
iPhoto nor iMovie could create image slideshows to a DVD playable on any standard, external DVD player without converting the data to the standard DVD format without either iDVD OR Roxio Toast Titanium.
Both iDVD and Roxio Toast will work all the way up to Yosemite.
If you want all the bells and whistles of iDVD, then you need to purchase the complete iLIfe '09 suite of apps, but do only a custom install to just install the iDVD app and iDVD themes and nothing else.
http://www.amazon.com/Apple-MB966Z-A-iLife-VERSION/dp/B0014X5XEK/ref=sr_1_cc_2?s =aps&ie=UTF8&qid=1426617694&sr=1-2-catco…
OR purchase, install and use Roxio Toast to create the proper DVD player, playable format.
http://www.roxio.com/
There is NO other options to be able to create a DVD player playable disc.
There is no "free" app that can create a standard playable DVD.
Sorry.
Good Luck!