When I got off the bus that takes you across the Thai-Lao Friendship Bridge, I was the only person who needed a visa-on-arrival so I thought it would be quick. But I arrived during the "dinner break" of the people doing that job and had to wait around for twenty minutes!
Only when the guy eventually appeared could I get the entry forms, which took some more time to fill out. But the guy was cheerful and his English was good. I told him I didn't have the photo mentioned on the form and he said:
No problem!
Back when I originally answered this question it seems I didn't have to pay any fee for not having a passport in photo, but both times I entered Laos in 2023 there was a ฿100 fee.
I also left some fields blank on the form such as previous and next destination, which are fuzzy or unknown since I'm hitchhiking without a plan and because I didn't know where I'd been staying and there are fields for address and phone number where you're staying, and also of a Lao contact.
This was also no problem.
I was concerned "no problem" might mean some unofficial charge was coming up. This was not the case.
There is a space for a photo in the top corner of the form. I think they had a security camera but if so that's separate from the passport photo. (I also could be mixing up with entering Thailand which definitely has a security camera and fingerprint sensor.)
The charges as of 2023 are only:
- The $40 USD visa fee
(All nationalities except Chinese and Vietnamese, for whom it's $20 USD)
- ฿100 THB fee in case you don't have a passport photo
- Friendship Bridge bus ticket(s)
฿30 THB bus ticket + ฿5 THB overtime fee for before 8.30am or after 4.00pm
The visa-on-arrival fee should be paid in USD. If you pay in another currency the fee is considerably higher. I've posted a new question about the current prices in Thai baht or any other currencies. The most common recent Thai baht price I've been hearing is ฿1,600 which is over $10 USD higher than the price in dollars.
There was a notice near the visa-on-arrival window about an extra $1 fee, I think for outside normal hours. I didn't have to pay. I neglected to take a photo or Google Translation of it.