Using a "screen" paragraph (see below)
The "screen" paragraph type may become very useful when creating tutorials. A screen paragraph may look very similar to an image at first sight, but it is in fact made up of a certain number of elements you can change.
You can start with a background image (usually a screenshot if you're creating a tutorial) and you may then add further elements to it: texts, speech bubbles, boxes, notes, frames or flags for example.
The huge advantage of the screen paragraph is the fact that you may change everything at any time, using a simple web interface. This also means that you won't need any advanced image processing tool to create screenshots for your tutorial.
Another big advantage is the fact that screens are multi-language, which means that you only have to create them once even if you're translating your tutorial - simple update the text boxes on your screenshot when adding a language, and you're done!