Image IDs

I've found out the hard way that if you upload an image into an article, then decide to copy and paste the image into a different article, the article preview shows the image successfully inserted, however when you publish the article the image is not displayed. This is because the image has not been manually uploaded to the new article, simply copied and pasted. The copy and paste action should automatically upload the image into the article to prevent issues when publishing - I had assumed it would have!

Thanks.