Get TinyMCE to use full image url instead of relative one

As it was previously pointed out, this the correct way:

relative_urls : false,
remove_script_host : false,
convert_urls : true,

HOWEVER, there is one thing to mention that will make you wonder why it's not working even though you have specified the proper text above. Ensure the false and true do NOT have quotes around them.

The following is incorrect:

relative_urls : "false", 

Make sure in the javascript initialization you are using, that you have these lines in it:

relative_urls : false,
remove_script_host : false,
convert_urls : true,

Read more: TinyMCE - URL handling options