Plan for about 2 to 3 business days for the mail to travel from InmateAid's office to the facility through the US Postal Service. That is the transit portion of the timeline and it is fairly predictable.
What happens after it arrives at the facility is less predictable. Every mailroom operates differently. Staff open, read, and inspect each piece of incoming mail before it is cleared for distribution. Some facilities turn mail around the same day it comes in, while others sit on it for several days before mail call. Weekends do not count since mail call runs Monday through Friday at most facilities.
A total timeline of 5 to 10 days from when you sent to when he holds it in his hand is a realistic range. It can land faster at some facilities and slower at others. The photos will likely go through the same inspection process and need to clear any content review before they are released to him.