I think the general "rule" is 5 per day, but that may be for the critique forum. If you use the upload feature when you post, it limits you to 5 photos per post. If you have your photos hosted someplace like flickr, or in the gallery on this site, you can link them to your posts and have more than 5. Of course the more images you have in your post, the longer it takes for that page to load.
"I thought that because fewer wolves meant more deer, that no wolves would mean hunters' paradise. But after seeing the green fire die, I sensed that neither the wolf nor the mountain agreed with such a view."
Aldo Leopold
If the images are attachments (hosted here) or from the Gallery (hosted here) then I think they will load faster.
Sometimes images from other sites load one pixel square. I had a spate of that yesterday evening where no-one's images from other sites were loading right, and when I checked with adblockplus plugin and flashed the border of the missing images there were just tiny flashing blocks.
I get annoyed with photos from other sites, because they sometimes get removed, or blocked if there's too much traffic, and it's possible to post images in threads so large that they don't fit my laptop screen.
Which is why I expect to find large images in the gallery, and the 800 pixel limit on thread images so they fit my screen.
It would be a bummer if Eric or anyone for that matter was limited on the number of photos he/they could share with us.
I understand the reasons for the critique section having a limit.