I thought it might be that. The only way I know to make sure everyone sees an image is to directly upload it to the thread using the ("Upload Pic or GPS Track" button on the lower right). That eliminates the hosting issues that sometimes pop up. It also avoids the issue of dead links if you ever change sites. Having said that, I'm not suggesting that you should do that specifically for me, but it does correct the issue and preserves the images in the threads.