In my opinion it's a politically smart move. I think it's the right move. If national unity is the goal, then use the nation's flag. Hopefully it will outlast both democratic leaders and dictators. A country is more than a 'President'.
Photos are only appropriate to monarchies.
E. Yosef, Eritrea Hanging photographs of the Head of State on display in public places appears to be an expression of solidarity with the person in power. Where there is a dictatorial regime or a country that has just witnessed a revolution, sometimes under the guise of democracy, hanging photographs of the Head of State may be an indication of the popularity of the revolutionary leader. This may explain the reason why the practice is very common in African and Arab countries. The new President Laurent Gbagbo of Ivory Coast appears to be changing the 'norm'. If anything what it does is create an aura of omnipresence in the minds of the people.