They do in fact seem to be in the correct order to me: running left to right and top to bottom, if we take the top of each photo to be the position of the event then they are actually chronologically ordered.
Since the photos have different sizes, and the descriptive text may also be shorter or longer, the tiling effect can give rise to a small amount of “distortion” – however there is no simple way to control that, I’m afraid, unless perhaps you knock out the code which positions them (in which case they would be laid out in a rigid grid with greater potential for wasted space).