There have been many images for the Northern Ireland players and management to take with them from France, from the luxurious base north of Lyon, to the goals against Ukraine, Michael McGovern's performance against Germany and the tactical coherence of the display against Wales.
Then there was the warmth of the relationship with a fanbase that has won friends across France, though the fact that two men, Darren Rodgers and Robert Rainey, did not return is tragedy that cannot be forgotten.
But one image from the Parc des Princes on Saturday pulled together quite a few strands.
It came as the dejected Northern Ireland team walked back from acknowledging the green -clad support in the stadium.
On the touchline the Wales staff and some of the players stopped their celebrating to move forward to applaud the Irish players.
"I don't usually get emotional coming off the pitch but I was close to tears," said captain Steven Davis. "Wales knew they were in a game today, they knew it could've been them [out]. It was nice of them to show their appreciation for what we tried to do today."
Davis, who along with Jonny Evans and Stuart Dallas, had a claim on being the best player on the pitch in Paris, has been a driving force within O'Neill's over-achieving squad.
This was a team which less than three years ago lost a World Cup qualifier in Luxembourg; Northern Ireland’s rise from that low has been remarkable. When the draw for Euro 2016 was made in Nice five months after that landmark defeat, the Irish came out of pot 5 and as such were expected to finish fifth, just behind Finland.
Instead, with O’Neill coaxing discipline, unity, defiance and occasional excellence from a group of players, many of whom play well below the Premier League in England, Northern Ireland trashed those small expectations.
They topped the group and made the European Championships for the first time in their history. This brought 2½ weeks in France that have showcased individual and collective talent and O’Neill’s tactical nous.
Admittedly there was a stop-start against Poland in Nice, when the scale of the occasion seemed to affect some, though it was only a 1-0 defeat.
Then came Gareth McAuley’s soaring moment against Ukraine in Lyon, where any anxiety was banished. Niall McGinn came on to score a second and by then the Will Grigg song was becoming the tournament’s unofficial anthem. Although ‘the Grigg question’ became tiresome, Northern Ireland were happy. As O’Neill said, they felt they “belonged”.
The three points gained against Ukraine proved to be enough to take the squad through to the last 16; McGovern’s exceptional effort against Germany was vital in delivering the goal difference that mattered.
Robbie Brady's header against Italy meant avoiding France and O'Neill did not fear Wales. And, as Chris Coleman accepted, Northern Ireland outwitted Wales, they just couldn't score. That was due to known limitations. It's why the former postman Conor Washington was included.
What O’Neill has done is expand ambition, and organise, so that individual deficiencies are masked by collective improvements. In that sense, he looks a coming manager.
The IFA have been candid about the get-out clause in O’Neill’s four-year contract and there is speculation about a job in England. There is a Premier League vacancy at Southampton and on Saturday night in Paris Davis, who plays his club football at St Mary’s, was asked about O’Neill following him there.
“Stranger things have happened,” Davis replied.
“There are going to be people looking at him, he’s done a hell of a job with us. There’s been an unbelievable progression in the last couple of years - we were close to getting into the quarter-finals here.
“I’m sure there’ll be plenty of suitors thinking he’s a possible candidate for a role. We’d like to keep him, like, selfishly. But I’m sure at some point he’ll go on to manage a big club side.”
There will definitely be a new club for McGovern, again possibly Southampton. At 31 – 32 next month – McGovern is late to the limelight and as he said on Saturday: “I’m not the sort of fella who would really enjoy it that much.”
But what Irish football needs is that limelight. In a traditional football city such as Belfast, there is now stronger competition than ever from rugby and Gaelic games. There is a more sedentary culture among the young. But O’Neill and
are guiding ‘Club NI’ and the restructuring of elite youth football across the North. The prize money from Euro 2016 will aid that.
Legacy was a word mentioned frequently when the squad had their send-off from the Titanic centre and Davis said that phone calls home have brought news of a place going “football crazy”.
The impact has been broad and narrow. There were three 1-0 defeats in four games but positives far outweigh negatives. As Davis said in summary: “It’s bit different to what we’ve had before, there’s a great unity between the football staff, the players and the fans as well.
“Obviously we’ve seen what it’s done back home, uniting people. We take a lot of pride in what we’ve achieved. We’ll have great memories.”