I made the same "mistake", though I don't think it should be; I'll report it
we are seeing some photos on the table. Why is "we see" =/= "we are seeing"?
"We are seeing" (present continuing) is not generally used in English to mean sehen except in specific circumstances. That seems to be Duolingo's policy, anyway, as it's one situation where it clearly prefers using simple present tense instead ("we see").
I always try and put something like 'we can see some photos on the table' and get it wrong because of the 'can'. But 'we see some photos on the table' sounds so weird.
That's not a good translation. "Various" has an emphasis on there being some difference between each of the photos, which manche does not contain. "Some" is a good translation that does not change the meaning or emphasis.