<texcode>
\starttext
\setuppapersize[A5][A5]
\setuppagenumbering[alternative=doublesided]
\starttext
\startpagemakeup[align=center,doublesided=no,%
Reference: http://www.ntg.nl/pipermail/ntg-context/2011/063030.html
Or, another solution (which can be tuned as at will), which relies on a
new feature in MkIV: there is also a layout with the same name as the
makeup environment and you can control the margins of your new title
\definemakeup[titlepage][pagestate=start,doublesided=no]
\setuplayout[titlepage]
[backspace=2cm,width=108mm] % 148mm is the width, 20 mm of backspace,
\bfc This should be the long, long, very long title\par
\stoptitlepagemakeup
This is the colofon
\chapter{Start here on page 3}
\dorecurse{20}{\input tufte\par}
</texcode>
== Scaled Full Page Image 1 ==
An elegant option is to extend the makeup mechanism to accept the background key:
\unprotect
\appendtoks
\setupbackgrounds[\v!page][\c!background=\makeupparameter\c!background]
\to \t_page_makeup_every_setup
\protect
Then you can use
<pre>
\setupexternalfigures[location={local,default,global}]
\defineoverlay
[backgroundimage]
[{\externalfigure[cow.pdf][width=\overlaywidth, height=\overlayheight]}]
\starttext
\startstandardmakeup[background=backgroundimage]
Whatever
\stopstandardmakeup
Next
\stoptext
</pre>
== Scaled Full Page Image 2 ==
Another way to use a full-page image includes:
<pre>
\startTEXpage
\externalfigure[cow.pdf][width=\paperwidth, height=\paperheight]
\stopTEXpage
</pre>