Before Pico i used Flatpress, very competent script i might add, flatfiles ftw!
Anyway, it lacked the picasa plugin i wanted so i just made one, perhaps not the best nor the most optimal out there, but that's it!
It is the only one for the moment, could you do it better? most likely, head over and do so here (Flatpress) :D
Support thread is here Flatpress Forums