As we have a house in my wife's village in Laos we go there fairly often.  My 5 year old son and I have UK passports so we need VOAs, which we get at Pakse International Airport.  It's a fairly painless procedure, but means getting a vignette that takes up a whole passport page.  

 

I'm thinking of applying for online visas for our next trip.  Does anyone have experience of doing this?  Is it straightforward?  I see that it is necessary to scan a coloured copy of the passport bio page and a passport photo.  I guess a photo is not sufficient (I don't have a scanner)?

I am only aware of people being able to get them. Saves time plus no full page sticker.

I think a good photo of your passport photo page would be acceptable. You might want to try a scan app for your phone. This one for android has good reviews. https://play.google.com/store/apps/details?id=com.indymobileapp.document.scanner&hl=en

For the photo you could take one on your phone and edit it to get the correct size (4 X 6 cm).

Be careful you are using the official site. https://laoevisa.gov.la/index  There are some bogus ones that have much higher fees than it does.