Why do PNGs with embedded HTML links not open on iPhone and only allow to save as image? My company email (sent from outlook pc) signature has social media icons at the bottom - images hyperlinked to facebook, twitter etc. The hyperlinks work perfectly when opened up on PC's and other android and windows based smartphones.

However, when received on an iPhone - tapping an image only allows you to save the image and the hyperlink isn't working.  

The files are PNG's and have had nothing different done to them.

The user who created the sig said that it was created through the option within Office 2010.
I'm sure that the datatype of IMAGE:PNG isn't set up to have clicks that have hrefs in them isn't set up to be detected and processed in the viewer on the iPhone.

Certainly appears to be a limitation in the image viewing code.

If you could save that image on your iPhone and send to your desktop over email, you could check if the href was being removed somewhere in the process, but I don't see an easy way to make this work.