I did not received a request to send IM5455. I was just told to send a letter of explanation. Can you share your letter? I already sent mine just with the picture and the letter and the email sent by IRCC below.
Sir, Madam,
Thank you for contacting Immigration, Refugees and Citizenship Canada. I am pleased to follow up on your request:
Permanent Resident card - Photo retake required
If you applied for a Permanent Resident card (PR card) and the Case Processing Centre requires that you provide two new photos, you must send them according to the photo specifications with, if available, the letter/email received to this effect or an explanation letter (including your complete name, date of birth and UCI) to the following address:
Address for new PR:
Case Processing Centre - PRC
P.O. Box 4500
Sydney, Nova Scotia
B1P 6L1
Address for existing PR (e.g., PR card replacement):
Case Processing Centre - PRC
P.O. Box 9000 ATT TLM/T3
Sydney, Nova Scotia
B1P 6L1
Please note that if you do not send the requested information within 180 days from the date of the letter, you will have to submit an Application for a Permanent Resident Card (PR Card) and include the payment in order to obtain a PR card.