A glaring omission is the ability to create a synth image from scratch. However, you can get the same result by copying an existing synth image, clearing it out and then adding your desired components.
William, Alexey - any chance of getting a "Create new synth image" menu item?
The Synthesized image is Cue type.
Each cue can contain a Frame (or animation), Text, Shape (abstract), Timeline-based show, Beam
sequence, Clock, DMX sequence, Synthesized image, a Sequence of other cues, or a Capture (many
other cues triggered simultaneously). In the lower left corner of each cue, you will see an icon. The icon
indicates what the cue contains. Below you will see a list of icons and the corresponding type of image.
Agreed. I have never seen how to create a synthesized image from scratch, and it appears to be an oversight.
To create them I simply copy an existing cue that contains a synthesized image, then edit it. When you're on the editing screen you can then create new synthesized images from scratch.