You should define a transparency mask for your image. The transparency
mask is a gray scale image. More or less you should write something as
this:
...
\pgfdeclaremask{MyMask}{Mask}
\pgfimage[mask=Mask]{MyImage}
...
MyMask and MyImage are the transparency mask and your image,
respectively, both in a image format used by beamer.
Daniel.
Nicolas Ferré ha escrito:
>
> When inserting a png image without background in it, I lost the
> transparency if I compile the document with pdflatex (I need it because
> I work on a beamer presentation).
> Any solution to keep the transparency ?
>
