Need UK size passport photo - can you do your own?

So, I live in a small community and the one big name store here says they don't have the ability to do anything but a US size passport photo. Is there any way I can use an online site and print my own? Has anyone here done that before and had the Spouse Visa approved/denied?

If it doesn't seem like a good idea, I'll trek into the big city hopefully during the weekend.

TIA!

So, I live in a small community and the one big name store here says they don't have the ability to do anything but a US size passport photo. Is there any way I can use an online site and print my own? Has anyone here done that before and had the Spouse Visa approved/denied?

If it doesn't seem like a good idea, I'll trek into the big city hopefully during the weekend.

TIA!

You can just send a US photo, lots of people have done that and been fine. 

Yeah, they'll accept US passport photos, no problem.

They don't even use the passport photo you send anyway, since it's the biometrics photo that is put on your visa... so the size doesn't really matter.

Thank you both! 

Also, I've not used this for a visa application, but I have for a British passport renewal and a phone camera photo, ordered online for passport photo size was absolutely fine. You just have to make sure you comply with all the photo requirements (i.e. white background, not smiling, no hats etc..). I'd therefore assume that it would also be ok for a visa.