The most likely cause of that was your images were too large, either in dimensions, file size or both. Please keep in mind that the largest monitors people use are usually around 1920x1080. Your camera might be producing pictures 2 or 3 times that size. Cameras produce large resolution images so that they can be edited without losing much quality. So, edit the size of your images and try again. Reducing the dimensions usually also reduces the file size.
When you use the upload system, the box that pops up to select your image files has a table that indicates how big your pictures should be. If they are larger than that, the forum software tries to reduce the size for you. Sometimes it fails because the images are just too big. That's when you see the security token message - which has nothing to do with security or tokens.
Jim, LRH webmaster