Because when pictures are posted, they are "remotely" stored (not in the Board servers), that is, the picture stays in a different computer/server while being shown in the boards. If you remove the picture or block its address (or if the computer is not online), it won't be available to be shown here.
Actually, that's another problem with posting too many images on a thread: the pictures have to be "downloaded" from where it's being stored, and sometimes that connection might not be as fast as with the computer where these Boards are located.
You can find where the image is stored by either finding the image location or viewing the image properties. It depends on system and browser you are using.
That's why when you post an image, you have to enter the "complete URL" of where it is stored.
Too technical?
malu
