Visa on arrival photos

Go online and check at the Vietnam consulate.
There are many scams doing VOA.

Just take the photo and trim it down to fit on your application. Always good to have a few extra photos so have your photographer give you a few more.
All you need is a head shot.  Keep it simple.  No problems.  No worries.
We use Vietnamvisa-easy.com.  Highly recommended.  Upon arrival take your completed documents to the “Landing Visa” area, have your paperwork completed and documents in order.  Hand in, take a seat and wait for your name to be called.  Pay the fee and you’re on your way.  Enjoy Vietnam. 
 
Yogi in DaLat.

4x6 is the standardised visa size photo, not the passport size, there's a slight difference

I just printed some 2"x2" for my Visa On Arrival and used the same ones for my 5 year visa application.

This may help.

https://www.myvietnamvisa.com/answers/S … -visa.html

Ok, I feel confident now to not over analyze this...thank for the inputs.

UPDATE:

Gee, it was the easiest thing. He even only asked $30 for 3 months Visa and I had not even filled everything in on the form. I had also not even signed the form. So they were not strict at all, what a suprise...and super friendly too.