+\wxheading{Alpha channel support}
+
+Starting from wxWindows 2.5.0 wxImage supports alpha channel data, that is in
+addition to a byte for the red, green and blue colour components for each pixel
+it also stores a byte representing the pixel opacity. The alpha value of $0$
+corresponds to a transparent pixel (null opacity) while the value of $255$
+means that the pixel is 100\% opaque.
+
+Unlike the RGB data, not all images have the alpha channel and before using
+\helpref{GetAlpha}{wximagegetalpha} you should check if this image contains
+alpha value with \helpref{HasAlpha}{wximagehasalpha}. In fact, currently only
+images loaded from PNG files with transparency information will have alpha
+channel but support for it will be added to the other formats as well (as well
+as support for saving images with alpha channel which is not still implemented
+either).
+
+\wxheading{Available image handlers}
+
+The following image handlers are available. {\bf wxBMPHandler} is always
+installed by default. To use other image formats, install the appropriate
+handler with \helpref{wxImage::AddHandler}{wximageaddhandler} or
+\helpref{wxInitAllImageHandlers}{wxinitallimagehandlers}.
+
+\twocolwidtha{5cm}%
+\begin{twocollist}
+\twocolitem{\indexit{wxBMPHandler}}{For loading and saving, always installed.}
+\twocolitem{\indexit{wxPNGHandler}}{For loading (including alpha support) and saving.}
+\twocolitem{\indexit{wxJPEGHandler}}{For loading and saving.}
+\twocolitem{\indexit{wxGIFHandler}}{Only for loading, due to legal issues.}
+\twocolitem{\indexit{wxPCXHandler}}{For loading and saving (see below).}
+\twocolitem{\indexit{wxPNMHandler}}{For loading and saving (see below).}
+\twocolitem{\indexit{wxTIFFHandler}}{For loading and saving.}
+\twocolitem{\indexit{wxIFFHandler}}{For loading only.}
+\twocolitem{\indexit{wxXPMHandler}}{For loading and saving.}
+\twocolitem{\indexit{wxICOHandler}}{For loading and saving.}
+\twocolitem{\indexit{wxCURHandler}}{For loading and saving.}
+\twocolitem{\indexit{wxANIHandler}}{For loading only.}
+\end{twocollist}
+
+When saving in PCX format, {\bf wxPCXHandler} will count the number of
+different colours in the image; if there are 256 or less colours, it will
+save as 8 bit, else it will save as 24 bit.
+
+Loading PNMs only works for ASCII or raw RGB images. When saving in
+PNM format, {\bf wxPNMHandler} will always save as raw RGB.
+