In my opinion the first one seems more reasonable >> 'Look at this photo' << than the second one.
"To see" is ...um...it is simply "to see" something, withoutattentions in the act of "to see" while "to look at something" indicates a little bit attention to the thing you are looking at.
Do you mean that you changed ? to . by "punctuation"?-- Yes.
Why should the punctuation be slightly different?-- 'Look at' is a voluntary action and can be commanded or suggested. 'See' is a natural reflex and cannot be so controlled, so it warrants a simple inquiry, '(Can you) see...?'
There is no perceptible difference in these two set ways of drawing attenti