[pdftex] wrong page breaks with image inclusion in pdftex

[Joseph Strus]

Hello all:
I've used pdftex for a while, but am new to 
working with .jpg inclusion.  I use plain tex.
I want to use a .jpg as a letterhead and I also
want to include figures 'inline' with text.

So, when I do something like:

\pdfximage height 4in {hello.jpg}
\pdfrefximage \pdflastximage
...
lots of text
...

The image is included correctly.
However, the page that includes
the .jpg seems to overrun and the page
break does not happen where it should, 
and I'm getting box overfulls that are about 
the size of the image.  Following pages all
have correct page breaks.

Does the image need it's own page?  I can't find
any references to this in the documentation.

Thanks in advance for any help.
Regards,
joe strus