I started a project in the wizard and saved it to work on later. I want to now add more photos and arrange them, but can't open the wizard and find a way to easily add new picture.
. . . . I started a project in the wizard and saved it to work on later . . . .
Which wizard did you use?
Depending on which wizard you used you have to do the following:
Photostor-Assistent
AFAICS once you have created a slideshow using this wizard , if you want to make any further changes eg add more images , you have to do this manually either in Storyboard mode or Timeline mode, adding any effects you require or copying an effect from an existing image and pasting to the new image(s).
Slideshow Maker
As above do this manually or in either Storyboard or Timeline mode add the new images where you want them to be, then select all the objects (Ctrl+A) and the run the Slideshow Maker wizard again selecting the required option. You will also be asked if you want to keep existing effects, if you click No then the entire slideshow will be remade.