Delete all Images. Edit 1. Hmmm.

[heslopian]

I watched an old man taking pictures Should a comma - or even better, a colon - go here?
mountains,trees and summer skies.
I watched a child cry for attention; This should be a colon, I think, as the next line lists the elements of this one.
screams and tantrums, tight-squeezed eyes. Elegant rhyme of "skies" and "eyes".
Which memory will last a lifetime? Why would either last that long?
Fading photos, sobbing years? This implies that the child's hissy fit has lasted for years.

The old man stopped and smiled benignly, Is "benignly" needed?
turned his lens towards the sun;
there on the pavement danced a circle,
ring of brightness, dancing fun. Another very elegant rhyme. Also a great description of sunlight.
Who will claim the greatest pleasure
now that they have swapped a tear? Swapped it with what?

The infant chased the dodging day glow Should this be "day-glo"? I doubt it, but that's what it feels like. If not, I'd recommend removing "day".
laughing at each twist and play; I really like "twist and play" in this context. It almost personifies the "glow".
in rheumy eyes a swell of recall,
rising joy of happier days. Nicely worded, moving couple of lines.
Old man too late to capture memories, Why? He's already been capturing memories with his camera, unless you mean that he's too old to remember happier times, but in that case where did the previous line's "rising joy" come from?
child too young to know that fear. What fear? The old man's forgetfulness, as conveyed by the previous line, seems more like a reality than a fear.

The sun slipped sudden, clouds occluding. "Slipped sudden" is a touch corny.
The game was over, brightness gone;
a click of shutter held the second,
boy and man, yet strangely one. Oddly effective slant rhyme of "gone" and "one". Also, I've just realised that the child and the old man are the same person.
One, because each shared the moment,
and in that instant all was clear.

Despite my nit-picking above, I really enjoyed this poem. The subtle interplay of images creates potent meaning; not to sound like a pot-smoking teenager, but it's totally deep, maaaan The precision of image is great; you make us see something as clearly as we would in a snapshot, then connect it to something else, and both help build a narrative. In short, I liked it. My critique is, of course, JMHO. Thanks for the read