If you want to display images with descriptions or comments, see Can I use Textpattern for a photoblog?

You can construct a simple image gallery like this:

1. Copy the default page template. Call it gallery. Find the main content block, remove any <txp:article.. /> tags, and replace it with something like this:

<div id="content">
<txp:image_index wraptag="div" break="" />
<txp:image_display />
</div>

You can use the standard wraptag, break and class attributes to control the layout.

2. Create a new section named gallery. Set Uses page to gallery.

3. Create one or more new image categories in textpattern > content > organise.

3. Upload some images via textpattern > content > images. Make sure each one has a thumbnail – you can use the create thumbnail feature – and assign it to one of your image categories.

4. View http://example.com/gallery/?c=mycategory (or http://example.com?s=gallery&c=mycategory@ if you’re using Messy URLs). You can click on each image thumbnail to view the associated image.

There are several plugins that provide more complex gallery features.