If you want to use HtmlHelper.ActionLink(..) extension method to produce something like a clickable image, you could get into trouble. In effect, the “linkText” string passed to HtmlHelper.ActionLink is automatically HTML-encoded by the helper method before producing the desired anchor element. So it seems somewhat impossible to make this sort of invocation work:

<%= Html.ActionLink(
"<img src='myImage.png'/>",
'TheAction', ...) %>

My solution to this problem was to write an extension method like this one:

public static string ActionLinkEx(
  this HtmlHelper h, string htmlLinkText,
  string actionName, string controllerName,
  object routeValues, object htmlAttributes)
{
  var builtCode = h.ActionLink(
    "*",actionName, controllerName,
    routeValues, htmlAttributes);
  return builtCode.Replace("*",htmlLinkText);
}

The method just wraps the standard HtmlHelper.ActionLink(..). This one prepares an HTML text made by a clickable asterisk (*) linking to the desired action method. Then my helper method replaces the text of the link (the asterisk) with the desired HTML code (passed using the htmlLinkText input parameter).