The author's first example is an instance of formal conflict. Once we reach panel three we question where the panel is going because it introduces a radical element (as the author observes) that seems disconnected from the first two elements of the sequence. This is enough to establish a formal conflict for us as it subverts the form established prior--it creates a narrative question, 'why is this here, what is the point, where is this going?' The final panel then resolves this conflict by reintegrating the material from the first two panels with the third.
And so even though there's no 'conflict' in the western traditional sense of the characters of the story combating, conflict still drives the story. It's actually pretty difficult to argue that stories don't require any conflict, as conflict is often an imprecise and overloaded category (think of all its different varieties) and really when people advocate for conflict they are advocating more generally for flux and change--e.g. the idea is you couldn't tell a story if every panel were the same image--you'd perhaps be saying something--making a statement or a proposition, but it wouldn't be a story. While a poem or a painting can often take the form of a one-line proposition, a story as I conceive of it is something more like an argument--it operates on the premise that certain bits of information are out of scope as we read and that patterns are interrupted then resolved into different forms as we glean new information--all narrative arts are necessarily time bound arts and thus more often called experiences rather than objects (e.g. a film is an experience b/c it relies necessarily on a time factor, where as the totality of an object might be consumed at a singular moment T, ignoring history--)