There is a limit to the file size and the number of pictures you can post. According to what it says here it is:
Allowed file types: gif, jpg, pdf, png, zip, mp3, jpe, jpeg
Restrictions: 50 per post, maximum total size 40000KB, maximum individual size 10000KB
But since Shane left there have been some changes made, and I don't know how accurate this info still is.
Judging by the size of the picture Warner could post, it is just under 5000 Kb. Maybe the other pictures were over 5000Kb and the file size limit is now 5000Kb. Just bringing this up as a possible reason, it could be something else. Maybe @TylerC