There is a connivence store that I usually go to on Dundas West between Elizabeth and Chestnut. Asian run, they have a photo studio in the back, and they also do it for around 10-15$ if I remember correctly for 2 or 4 photos, they give good deals too. You could go anywhere though, most places have all different specs for US visas, PR, Passport, etc. Shouldn't be a problem, just find the closest place that is convenient to you.