In the first picture there is a castle(,) while(,) in the second picture(,) there is a small house.

[dewedfrost]

In the first picture there is a castle(,)1 while(,)2 in the second picture(,)3 there is a small house.
Hello! I'm wondering if the commas in brackets are necessary or optional.
I think 1 is necessary, 2 and 3 are optional. Do you agree? I've already searched for some advice in the Net, but I'd like to know your suggestion.

 

[jutfrank]

I probably wouldn't use any commas at all. The sentence is short and simple enough to read very easily.

1 can be well-justified, if you want the reader to make a slight pause.
2 is wrong. You can't pause there.
3 is unnecessary.
4 (after In the first picture) is similarly unnecessary.