On an eDocBuilder template, multiple images that are to be used on the fields in the template can be uploaded to the Assets tab for the template. It is not possible to download these images from the Assets tab, or from the Field Setup area of the template.
But if you edit your template in eDocBuilder and go to the Field Designer tab, then when you select a field that is referencing the asset images, you can click on the image and get a vertical three dots button on the image. That button has a menu option that you can use to download the asset image.
This does have to be done for each image referenced on the field, but it works on both Forms and Interactive Designer templates. Please see the articles on Field Designer for more information about using this area of the templates.