They are even more poignant, now, the images of Jack Layton this spring.
Hobbling from event to event on a cane. Slowly getting his colour back, the spring in his step returning, dancing a jig in a Quebec sugar shack. His familiar smile wider than ever, as it became clear that years of hard work were paying off in the electoral breakthrough that others had dismissed as a pipe dream.
Even at the time, given his recent health problems, it was impossible not to wonder if this would be the final time we'd see one of this country's very best campaigners hit the hustings. But nobody had expected that question to be thrown into such sharp relief, so quickly, as it was when the distressingly gaunt NDP Leader announced on Monday that he's temporarily stepping aside to fight what appears to be a very serious new occurrence of cancer.
It would be a mistake, as anyone who has watched him over the years could attest, to count out someone as determined as Mr. Layton. But there is another and even more uncomfortable question that politics watchers cannot help but puzzle over: What is the New Democratic Party of Canada, what are its identity and its image and its limitations, if Jack Layton is not at the helm?
That, really, has been the issue facing Mr. Layton himself since election night.
He has been nothing if not forward-looking in his long and patient struggle to change the culture of the NDP, wanting to leave to his successors a party that replaced the Liberals as the centre-left alternative to the Conservatives. With the New Democrats now the Official Opposition, he could step away tomorrow having ostensibly achieved that. But it won't mean much if that new status isn't built to last.
There is no overestimating the extent to which Mr. Layton's personal popularity has propelled the NDP's surge. By far the most charismatic of his generation of federal leaders, he has consistently polled ahead of his party. With each of the four elections under his leadership, the NDP's image has revolved more and more around his own. And the more Canadians have seen him, the more they've liked him - taking the party from 8.5-per-cent national support in the last election under his predecessor to nearly four times that figure earlier this year.
But it is not just about how the public sees the New Democrats; it is also about how they see themselves.
Theirs is a party that could very easily fracture, both between its idealists and its pragmatists, and between its newly dominant (and quasi-nationalist) Quebec wing and everyone else. Mr. Layton is the New Democrats' glue - partly because New Democrats have to defer to his popularity, and partly because he effortlessly straddles these different groups. But if he's all that's holding them together, then sooner or later they'll fall apart.
Mr. Layton's recommendation for an interim leader suggests he understands this danger. There are more obvious choices in the NDP caucus than Nycole Turmel, a rookie MP scarcely known outside Quebec. But unlike deputy leaders Thomas Mulcair and Libby Davies, the former head of the Public Service Alliance of Canada isn't seen as the standard-bearer for any particular faction of the party. So beyond the obvious consideration that she's not known to have long-term leadership ambitions, there's some hope that she'll be able to prove it's not just Mr. Layton who can straddle.
On that note, a senior New Democrat suggested following Mr. Layton's announcement that his temporary absence - provided that it is indeed temporary - presents the NDP with a useful dry run. Here is its chance to prove to all the doubters that its sense of common cause runs deeper than any one person.
But of course, there's a bit of an asterisk there. Mr. Layton's presence continues to loom very large, and rallying around an ailing leader's brave struggle is not the same as building toward a future that doesn't involve him.
The real challenges will come when the NDP holds its next leadership contest, and when the winner of that contest has to really put his or her own stamp on the party, then face voters.
By all rights, Mr. Layton should get to help prepare the party. The next four years should be about grooming potential successors; about making sure that voters who cast ballots for the NDP on a lark become long-term supporters; about transitioning the brand to one that builds on his legacy, rather than one that revolves around him.
In the past, Mr. Layton has likened building his party (particularly in Quebec) to constructing a house. It's not always pretty, and it's hard to really visualize the finished product until it's done. But put in enough work, and you'll eventually make believers.
It's started to look awfully nice, that house. But eventually, it will be left to others to test the foundations. New Democrats, along with the rest of us, can only hope that Mr. Layton will get to finish building them himself.