I have been reading the forum & PDF guide regarding the Number of Photos to be sent . This is for 2nd stage of the Application & the CIC visa office is Buffalo, NY.
MY questions are
1) 1 pasted & 3 in envelope ?
2) 1 pasted & 4 in envelope ?
3) No pasting & 4 in envelope?
'Enclose the photos of each person in an envelope and seal the envelope'
"Write your name and date of birth on the outside of the envelope"
"Staple the envelope to your application form"
He didn’t mention to paste any photo to the application paper
So I think that u have to enclose all 4 photos in the envelope
Good luck