Photoshop Elements 15 v. Premiere Elements

I downloaded the Premiere Elements trial version thinking it was just a more enhanced version of Photoshop Elements, but I found that I need to have the Photoshop Elements to work with the photos.  I found that with the Premiere edition, I could work with my video's, but not the photo's.  So my real question is are they in fact two different application.  I am not a big video person, and when I do want to edit any I already have Roxio.  I am getting ready to purchase it, but I want to be certain what I need to buy