Lol no. ^^ Just googled halloween dogs.
I always just click on the picture icon and add the url there. If the picture is on a website, you can right click on it and go to properties and get the url from there. No uploading required, just copy and paste.
If you had them uploaded to your photo gallery, and used
that url to insert the images, then deleted them from your photo gallery, then that url no longer exists.....so the pictures won't show up.