为什么包含图像的锚标签在Iphone的邮件应用程序中不起作用？

I"m doing a HTML newsletter for a client, using thunderbird to send it, and everything works fine in all browsers and mail clients, but the anchor tag containing an image, don't work in Iphone's mail app. Every time i click the image, the app ask me if i want to download the image, It doesn't take the "href".I"m doing a HTML newsletter for a client, using