Update:I was able to get this to work, although it isn't very effective in handling multiple attachments, or anything other than an image.Since I couldn't find an event to watch for the attachment editor loading, I used the mouse hover event to change the way the link is handled.
app.attachmentList = app.editor.attributeInspector._attachmentEditor._attachmentList;
if (app.attachmentList) {
app.selectFeatureHandle = on(app.attachmentList, "mouseover", function() {
var link = domQuery('a', app.attachmentList)[0];
var temp = domAttr.get(link, 'href');
if (temp != '#') {
app.attachUrl = temp;
domAttr.set(link, "href", "#");
domAttr.set(link, "target", "_self");
link.innerHTML = '<img class="attachment" src="' + app.attachUrl + '" + alt="Attachment" />';
app.viewAttachmentHandle = on(link, "click", function() {
attachmentDialog.set('content', '<img class="attachment" src="' + app.attachUrl + '" + alt="Attachment" />');
attachmentDialog.show();
});
}
});
app.clearFeatureHandle = on(app.map.infoWindow, "hide", function() {
app.attachUrl = '';
app.clearFeatureHandle.remove();
app.viewAttachmentHandle.remove();
});
}
This code will load the image in place of the link text, as well as add a dojo popup dialog when the image is clicked. Any other suggestions would be appreciated.