writer html image border does not display in browser

Running Version: on Linux Mint 18.1
I create a document in writer which contains an image. In Format > Image > Properties I add a border, this displays as expected. I save the document as htlm and open it in Firefox 57.0.1 and the document displays everything except the image border.
Have I missed something or is this a bug?

Hello @micksulley,

i could not reproduce this problem in Version
Inside your Writer document, select the menu "File : Preview in Web Browser" … Does it show a border there?