Today's slide show shows this picture in episode 1190, in the real time 1840 storyline.
Thanks for pointing that out (I haven't been checking out the Robs slideshows lately):
(http://www.dsboards.com/eventimages/0115ds_13.jpg)
1971: Ep #1190 - Having freed herself, Daphne searches
through a secret passageway for a way to escape.
Clearly it's no spring chicken in 1840, even though it looks to me as though it would have been in a later era. Very strange.
That seems to be par for the course with most of the portraits. Isaac looks like he's dressed in Victorian garb, yet he was alive in the 17th century. Apparently many of the Collinses were VERY fashion forward. [snow_cheesy]