Article Title	 	: Netscape and GIF images
Creation Date		: 04/07/97
Message ID		: CGTNPQ
Last Update		: 04/07/97
Expiration Rules	: unknown
Location		: NCD-Articles/Applications/
=================================================================

Problem Overview:
================

NC will hang when displaying a .gif that appears to be a transparent
GIF. A normal GIF gives you an entire picture to paint in a rectangle. A
transparent GIF only wants to display certain parts, leaving the background
alone.  There is one obvious way to implement this in X, so Netscape probably
used it.  However, it is an extremely memory and CPU intensive process.  This
is complicated by the very complex image. It's further complicated by Netscape's
default image loading, which displays it while it's being loaded.  Yet another
complication is Netscape's extreme method of handling X out-of-memory errors --
it simply ignores them and goes on, assuming the display will eventually catch
up.  This process happens to be hung if that the image partially loaded and 
displayed.  As Netscape gets a bit more of it, it displays (probably restarting
from the top) the next bits of it.    

Since it is a tranparent GIF, it takes a huge amount of CPU and memory for
each display.  As some point, the terminal runs out of memory and complains.
If you wait long enough Netscape 'finishes' sending the picture and things
are working okay again.

Solution:
========

This is not a bug in the X server and there is not anything we can do 
to fix it.

Potential Workaround:
====================

Configure Netscape to wait until the image is loaded before displaying.

Set this via Netscape->Options->General Preferences->Images.  Change
'Display Images' to 'After Loading'. Restart Netscape again.