It is not an impossible question, therefore you asked it, and somebody will answer. I noticed Alexei's photos (from Tsarskoe Selo's gardens in 1915), Alexei aboard the Standart in 1912/3, with his mother in 1913, one photo of Tsarevich from 1910, and indeed several formal ones of Alexandra, from 1890's up to 1917.
EDIT: There are several larger photos of Nicholas' study, and photos are more visible in those. ;-)