True. I am in my mid to late 50s. I can look anything from 45 to 65 in photos. Depends on the angle, the lighting, what I'm wearing, if I have make up on etc etc... I had some pics taken at a wedding last summer and several people said I looked 10 years younger - just mid 40s. And I looked about one and a half stone lighter ... (I am 3 stone overweight.) I had a nice flattering outfit on, and lovely make up, and my hair was done beautifully. And the angle of the photos were good.
Had a pic taken by DH last week (twat taking it when I wasn't looking!) and I had no make up on, hair like Worzel Gummidge, and scruffy leggings and a t-shirt on... I looked 65, and a stone heavier than my weight because of the shitty unflattering angle! As you say, it's hard to tell from a photo, as there are so many variables...
But yeah for sure, virtually everyone looks their age within 5 years. IMO!