Copying and pasting this image into Writer leads to Writer becoming very slow to respond. This image uses a data: URI to embed the image data in the HTML page.
The above image was generated by Google image search results; the original image from http://xkcd.com/1210/ is licensed under a Creative Commons Attribution-NonCommercial 2.5 License
Copying and pasting this image into Writer causes no problems; writer takes a few seconds to download and display the image, then responds as normal. This image uses a https: URI to reference image data downloaded from Google servers.
The above image was generated by Google image search results; the original image from http://xkcd.com/1210/ is licensed under a Creative Commons Attribution-NonCommercial 2.5 License
Decoding the base64-encoded data: URI produces the same file content as is downloaded from Google via the https: URI.
Copying and pasting this image into Writer, the image is not displayed, but Writer otherwise responds as normal. This image also uses a data: URI to embed image data in the HTML page.
The above image was produced specifically for this test.