Graphics missing in PDF/PS, SGML export??

[Alex Brown]

I'm a relatively unsophisticated but enthusiastic LyX user;  I've been 
following its development for years.  I'm using LyX 1.3.1 on RedHat 9 
(installed from lyx-1.3.1-1rh9-qt.i386.rpm) with generally good results, 
creating structured docts for multiple target formats, esp. PDF, also 
PS, HTML, and text, using Linuxdoc SGML export from a LyX master created 
with a Linuxdoc template.  I have done this successfully before with 
previous versions of LyX.  Today I'm puzzled by absence of graphics in 
any of the generated products, including PDF generated by either 
(buffer-export pdf) or pdflatex export.  My memory is that this worked 
fine in earlier versions.  I can't imagine that this is really broken, 
but there does not seem to be any configuration at either the document 
level or the individual figure to control this.

Any ideas?  Thanks in advance.

Alex Brown <[EMAIL PROTECTED]>