Does DXImageTransform.Microsoft.AlphaImageLoader work over SSL? I've been trying to no avail to get this to work, but it does work fine over an insecure connection.
All of the PNG hacks I've found use this method, and search results haven't yielded anything for me.
The Cause
Anytime you get the security error about some content not being secure, it is because something is being linked to that is coming from a non-HTTPS (insecure) connection. Tracking it down led us to see that it was some CSS tags that allow for PNG transparency in IE6 and IE7, using the CSS "filter" property and the "AlphaImageLoader" plugin. Here's the particular line of code:
filter: progid:DXImageTransform.Microsoft.AlphaImageLoader(src='images/facebox/tr.png', sizingMethod='scale');The Solution
So the solution is to use a full secure URL with "HTTPS://" to the png image. IE sees that AlphaImageLoader as a plugin. And all plugins in IE 6,7 are required to only reference cached images. The images cached are not HTTPS (or secure), and so the secure content error popup is shown when the AlphaImageLoader requests the images. So the following request worked correctly.
filter: progid:DXImageTransform.Microsoft.AlphaImageLoader (src='https://www.livingroad.com/images/facebox/tr.png', sizingMethod='scale');Oh, and don't try to use spaces in the URL for the AlphaImageLoader! This is another known bug in the plugin.