It's very simple to create an image gallery with inCMS.
Please make sure that all the pictures you want to add to the gallery are saved in one folder in your files.
Click on the green plus-icon on your website and select "gallery".
Afterwards click on "folder from files" and choose the folder with your pictures for the gallery.
In addition you can decide whether your gallery is divided in three or four rows.
That's all you need to do to create the image gallery.
When you click on "preview" you can see that incms created a wonderfully designed gallery with all the pictures from your selected folder.