5 posts per day for 2 days is just fine with me. Most people who have troubles with that are the ones who decide to pad their numbers with junk posts (#1,
#2 ,
#3 ,
#4 , etc).
No external links for the first couple of days is also just fine. If it is important, describe it. There are a few ways people get caught on that, but generally posting a link to an ad, "is this any good", but it also helps weed out those masquerading as concerned individuals who are just posting their website links for personal profit. So.. just fine. And, of course, those individuals who are posting pure SPAM.
As far as the photo restrictions, that wasn't historically on the site, but it got caught up in the web when photo and attachment systems were updated a couple of years ago. Were photos ever a problem that this is solving? Personally I'd put in an internal exception allowing internal links to either
https://www.bikeforums.net/ , or
https://cimg6.ibsrv.net/gimg/bikeforums.net-vbulletin while maintaining a no external link policy.