Adding Automatic Crossfades to a current project

I have made a timeline with all pics and videos right next to each other. Now I would like to add the 1 second crossfade to the entire project without having to start over again. Is there a way that I can just add the crossfades to the entire project, before I render? Even though I had the automatic crossfade button highlighted, it didn't overlap the pics/videos till I went into options-preferences-editing and check the "overlap automatic multiple selected ojects when added" box.