Images
You can add a single image by putting it in the images folder and then reference it:
image:ich.jpg
For many pictures you better add a whole folder of images in one strike. Simply create a folder (here nature) as subfolder of the images folder and put all the photos of a specific gallery in there. Then simply add the following to a mobiki page:
images:nature
If the folder is empty of does not exist you will see nothing. See here, how it looks with some heavily compressed public domain example images from pixabay - sorry for the quality:
