When I posted my Baldwin Lakes trip report, the paper clip function only has 10 spots to add images so it may be the limit per post but I got around that by using the attachments to post more new photos rather than having it repeat the ones already posted. Make sure that you are in Advanced Mode (click on Go Advanced button). After you upload all the photos using the paperclip function scroll all the way down to the bottom where it says Additional Options; Attach Files, Click on "Manage Attachments" then a window pops up where you can attach more photos.
By the way, I usually resize my photos to around 1 MB for faster upload.