PhotoLine has to basic working modes: the document and the picture mode.
Documents are used for creating greeting cards, labels and things like that. Pictures are used for web graphics or if the result will be used in another application.
Nevertheless documents and pictures are very similar. Both consist of layers and nearly all functions can be used on both. The main difference is, that the first layer in pictures is always an image layer. This image layer is called background layer and defines the size of the picture. If the background layer gets smaller, the whole picture gets smaller. Documents behave differently. On creation its size is defined. After that an document containing a single page is created without any layer. Afterwards you can add layers of any size to this page. Documents can contain several pages, picture can‘t.
In this manual both terms are used synonymously. If documents and pictures behave differently, it is explicitly written.
To change the working mode of an existing document or picture see chapter 4.8 "The Attributes Dialog".