Show current item's attachments on the form

nintex-show-attachments.js

/* In the context of a Nintex form in SharePoint: 
/* use jQuery (NWF$) to fetch the attachments of the current list item and display them 
/* on the form, using a DIV element inside a Multiline Text Control as the container. */

NWF.FormFiller.Events.RegisterAfterReady(function () {
    /* CONFIGURATION */
    var siteURL = "https://site.com"; // no trailing slash
    var listName = "A List of Items with Image Attachments" // use the list display name; 

    var itemId = GetUrlKeyValue('ID'); // or ({ItemProperty:ID}) if you are embedding the code into the form
    var url = siteURL + "/_api/web/lists/getByTitle('" + listName + "')/items(" + itemId + ")/AttachmentFiles";

    var query = NWF$.ajax({
        url: url,
        type: 'GET',
        headers: {
            'accept': 'application/json; odata=verbose'
        }
    });

    /* when the query returns data */
    query.done(function (data) {

        /* get the actual results from the data blob */
        var results = data.d.results;

        /* identify the element to hold the images */
        var target = NWF$('#atch');

        /* create an IMG element for each result, 
        i.e. each attachment URL */
        var attachments = results.map(function (result) {
            return NWF$('<img/>', {
                src: result.ServerRelativeUrl,
                alt: result.FileName,
                /* style the images as thumbnails */
                style: "margin:5px;width:100px;height:100px;float:left;"
            });
        });

        /* add the images to the target element */
        attachments.forEach(function (element) {
            element.appendTo(target);
        });
    });

    query.fail(function () {
        console.log("Query Failed");
    });
});