Which preposition you use can be personal preference, and it can also convey subtle differences in meaning.
Here, the writer may have used 'from' as opposed to 'of' to suggest that the pictures were taken at the wedding, but not of the wedding, per se.
Pictures of the ceremony itself, and of the bride and groom are clearly 'of' the wedding. But what about pictures of the guests at the wedding? Perhaps when they were socialising before the wedding itself, or after. To me, 'from' is a better fit for pictures such as those. Modern western wedding pictures often include pictures like those, as they allow the couple to see what happened when they were not there, and remind them of the friends and relatives that attended.