[Zope] PCGI and images not displaying

[bruno@xs2.greenpeace.org]

Hello

My set up: Linux (X/OS distribution based on RedHat 6.0), Zope 2.1.6
+ 
PCGI + Apache 1.3.9

We have a DTML document that shows an image based on the selection 
from the user, something like this:
<img src="images/<dtml-var card_id>/<dtml-var picture>"> (I snipped 
all the rest because it's of no interest here). The image is 
stored as an object in the ZODB. 
When the user requests that page, sometimes, the image is not
returned 
to the browser. What I see in the log from Apache is a return code
304 
(not changed) and a return code 200 in the Z2.log ... Does anyone 
knows of this? Is there a workaround besides putting the image in the 
filesystem and serving it as a URL from Zope only?

TIA.

/B