"I look forward to our negotiations this week", said Michel Barnier, the EU's chief Brexit negotiator, while giving a "warm welcome" to his United Kingdom counterpart, Secretary of State for Exiting the European Union David Davis.
Mr Davis said they made a "good start" at last month's preliminary talks - but it was now time to "get to the nitty-gritty". "We need to examine and compare our respective positions in order to make good progress".
Barnier said: "We will now delve into the heart of the matter".
British diplomats said the documents were still in Mr Davis's bag at the time the photo was taken.
As doubt for and objection to Brexit continue, progress favorable to those in support of the breaking away has been made, creating a silver lining for the closely watched second round of talks.
Photographs of the brief meeting showed grim-faced European Union negotiators with large sheaves of paper across a table from a grinning, empty handed British team.
The British side had urged over the past months an immediate start of trade talks, but agreed last month that key issues of Brexit be dealt with first.
But May's minority government remains fragile one month after the snap June 8 election in which her Conservative Party lost its majority, leaving the European Union wondering whether she can actually formulate a coherent Brexit policy.
Over the weekend, Chancellor Philip Hammond angrily accused Cabinet rivals of trying to undermine his agenda for a "softer" business-friendly Brexit prioritising jobs and the economy.
May's spokesman told reporters on Monday that she would be "reminding her colleagues of that at the cabinet meeting tomorrow.of their responsibilities and making the point that ministers across government need to be focused on getting on with delivering what the British public wants".
Hammond himself acknowledged that ministers were divided on other elements of Brexit.
"The plenary meetings [of the Brexit talks] will show us whether there is a realistic basis for agreement or whether the British government can not move at all because of its own problems", said Elmar Brok, a German centre-right MEP who helps coordinate the European parliament's position on Brexit.
Davis added that apart from citizens' rights and the UK's exit bill, Northern Ireland issues are also a priority of these talks.
The four days of talks are set to also address more detailed concerns such as Britain's future in Euratom, the EU's nuclear safety agency, and the role of the European Court of Justice, the EU's top court.
European Union leaders are set to decide at a summit in October whether there is enough common ground to move on to trade talks. Unsurprisingly, the Brits have expressed opposition to these figures; Foreign Minister Boris Johnson labelled the sums "extortionate", saying Brussels can "go whistle" for the money.