por fin soporte para PNG en IE 7.0

[asinox]

Pues ya tendremos el soporte para archivos png en internet explorer 7

Portable Network Graphics (PNG) - Internet Explorer 7 adds support for Alpha Channel Transparency to PNG so that Web designers can implement innovative and complex overlaid graphical designs. Note that only Alpha Channel Transparency has been added to PNG for Internet Explorer 7.

aqui mas informacion al respecto : Mas aqui

Saludos