I had a little trouble but this is what I did myself (community peeps please correct me if I'm wrong!)
Define the image in your model as:
image: {
type: Types.LocalFile,
dest: 'path/to/files', prefix: '/to/files',
filename: function(item, file){
return
item.id + '.' + file.extension
}
}
in the keystone.js file, make sure that the folder where images will be uploaded is set:
keystone.set('static', ['path','to', 'files']);
I think there is a type: Types.LocalFiles, option as well for multiple files... quick googling:
This is what I found most helpful on this: