Several suggestions for image support

[David Kastrup]

PNG images support transparency.  Emacs can't make use of it.  You can
only have Emacs declare a particular color as transparent.  This is
dissatisfactory.  It should tell the PNG decoding routines Emacs'
background color for the purpose of transparency.

I would find it important if an image specifier could restrict the
displayed portion of an image.

The reason is that large images always appear as a single big
character to Emacs.  If I could split such an image into a bunch of
smaller images, I could walk through it with the cursor.  But it
should only be necessary to instantiate the complete image itself once
for this purpose.  Of course, one should find a way that does not
cause all of the subimages to be entered separately into the image
cache.

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum