While playing with OpenOffice in my research for Files that Last, I came across a preservation risk. I copied an image from a website and pasted it into a text document, then looked at the resulting XML. The image data wasn’t anywhere in content.xml or anywhere else in the overall ZIP document. Instead, I found this:
<draw:image
xlink:href="http://plan-b-for-openoffice.org/resources/images/x180x60_3_get.png.pagespeed.ic.fjV0teeVb_.png"
xlink:type="simple"
xlink:show="embed"
xlink:actuate="onLoad"/>
The source for the image is on the Web. This means that if the URL stops working, the document loses the image. That’s a poor plan for long-term storage.
The way to avoid this is to use Edit > Paste special and paste the image as a bitmap. It can be a pain to remember to do this. You may be able to catch images that are pasted by reference, since there can be a brief delay while just a box with the URL is displayed before the image comes up.
Sneaky little preservation hazards like this (and the earlier one mentioned with Adobe Illustrator files) are the kind of thing you’ll find when Files that Last comes out.
Mad File Format Science 
I tried to replicate this with LibreOffice (v. 3.4.3) and got identical results. Did you report this as a bug with OpenOffice? I’ll try to do this tomorrow for LibreOffice (I’ll refer to this blog post).
For some OO/LO users the implications of this could actually be nothing short of dramatic, I’d imagine. Great find, in any case!
I assumed it’s a “feature,” though an ill-conceived one.
Report it as a bug. If they want to keep it, let their response be on record.
Quick update: just did a search in the LibreOffice bugtracker and came across a number of related issues. This one caught my attention in particular:
https://bugs.freedesktop.org/show_bug.cgi?id=52547
So apparently (well, in LibreOffice at least) what happens exactly also depends on which browser you’re using, and which version. Don’t have LibreOffice installed in the office here, so I can’t do any further tests right now.
With Safari on the Mac, it’s even stranger, though more obvious. If I do “copy image” and paste it into an OpenOffice text document, just the URL as text is pasted in. I pasted the same clipboard into Photoshop as a sanity test, and it pastes the image there.
Did you file a bug at https://www.libreoffice.org/get-help/bug/ on this or contacted the User Experience team at: http://nabble.documentfoundation.org/Design-f1935996.html or http://nabble.documentfoundation.org/UX-Advise-f3619688.html ?
Using linked images is a great feature within OpenOffice: Just break the images links by using the link dialog /Edit/Links…/
For the record, this is an 8 year old bug: https://issues.apache.org/ooo/show_bug.cgi?id=37652
You should vote for it!
Of course you can break it with the menu mentioned above. But default behavior should be with the least data loss risk possible. When you paste something, you expect the content to be kept inside the document.