I'm not *completely* sure that this is a bug, but...
I inserted a perfectly ordinary PDF graphic called
"BadUG.pdf" (generated by OmniGraffle) into a LyX document. The first
time I tried to preview the document after doing so I got the not
unfamiliar "Cannot determine size of graphic" LaTeX error. Oddly (?),
the error window reported that LaTeX was choking on a file called
"BadUG.png" that LyX had created, rather than BadUG.pdf. (I'm
guessing that BadUG.png is generated because that is the format that
LyX uses to display graphics in its own editing windows.) Adding
bounding box info and specifying a scale for the graphic did not solve
the problem. Inadvertently, I found a workaround when I decided to
have a gander at the LaTeX code that LyX was generating. Upon
exporting my LyX document to a .tex file (via File -> Export), the
Skim preview of my document automatically updated and, lo and behold,
there was BadUG.pdf, placed just where I wanted it in the document.
(Great, but WHY? I only asked for the .tex code, not that pdflatex
*compile* it.) Moreover, I was presented with a dialog box asking me
if I wanted to overwrite BadUG.pdf -- which suggests that the LyX code
is exporting the filename "BadUG.pdf", not "BadUG.png", which really
makes me wonder why LaTeX is choking on BadUG.png when I try to
preview from within LyX; you'd think that the code that is exported to
a .tex file would be identical to the code that is handed to pdflatex
when you preview.
Ideas appreciated. My workaround of exporting to pdflatex is less
than ideal, as I have to invoke it via the menus every time I want to
preview a change in my LyX document (instead of just clicking a handy
button -- poor me! :-). I've got a LyX bug report filled out and
ready to go but thought I'd get some feedback from the list first.
Chris Menzel