(T10)</b> 48-bit RGB, binary transparency, no background color:<br>
<img width="85" height="62" src="./images/png/rgb16_t.png" alt="[Test image]">
</p>


<h3>Grayscale alpha transparency</h3>

<p>Expected result:<br>
<img width="95" height="72" src="./images/png/resultga.gif" alt="[Test image]">
</p>

<p><b>(G1)</b> 16 bpp grayscale (8 gray + 8 alpha), includes background color:<br>
<img width="85" height="62" src="./images/png/gray8a_bk.png" alt="[Test image]">
</p>

<p><b>(G2)</b> 16 bpp grayscale (8 gray