I cannot see a way to include screen shots when sending a "Report a problem to Quicken Support. It defaults to a screen shot of the current screen, but there doesn't seem to be a way to change it or add to it.
Click the blue "Attach additional files…" button.
Note that the resulting file chooser will default to text files and you'll have to change it to image files.
Un-check the "Include screenshot" to get rid of that from your report.
@Rocket J Squirrel - Thanks! I didn't see that you could change the file type from txt to jpg.