Because drawing many dots takes a long time with our flying robot, we primarily make images of faces given that faces are easy for humans to recognize. The iconic image of Che Guevara makes for a good source images given how widely his image is recognized.
Stippling with aerial robots project page for the publication at Computational Aesthetics / Expressive.
This video produced by the McGill University newsroom provides a high level overview of the project.
The supplementary video for the conference publication, showing time lapse videos of various portraits being created.