If you’re in the US, dont go to chain stores like Walgreens that take passport photos because they usually take only US passport specs. You need to go to a professional studio preferably those that specialize in immigration photos. Before that, print out the exact photo specs provided by IRCC and discuss with the studio over the phone. Take the specs with you for the appointment and show it to the photgrpaher before taking the picture.
If the photo doesnt meet IRCC standards it will be rejected and you’re probably looking at longer processing times to finalize your application.
Just type in gmaps for passport photos and find a professional photo studio. Costs around 30$ per person but worth it. Ask them in phone before going if they stamp and if they know the standards for Canadian passport photo.