singlepic won't show in the post

Hello,

When I adding a singlepic with these shortcode for example: [singlepic id=1 w=320 h=240 mode=web20 float=right]

Then I can’t see an image on my post, instead i see the Alt-name of the picture.
The source code is: <img class=”ngg-singlepic ngg-right” title=”img_3822″ alt=”img_3822″ src=”https://www.example.com/index.php?callback=image&pid=1&width=320&height=240&mode=web20″&gt;

How can I fix it?

Used Nextgen Gallery version: 1.9.6

https://www.ads-software.com/extend/plugins/nextgen-gallery/