Display image from database

Hi to all,

I have a database with products and images, all works fine.
However not all products have images so when visitors
click on the article-number that supposed to display
the according image they get to view this 'default' image
with that little red-x on it (image not found).
Is there a way to change this "red-x" image into
some other image i created myself. (e.g. NoImage.jpg or .gif)?
To explain the further,
Database result wizard 'lists' the products with article-number and
smal description. The artcilenumber-field has a link to product-information
page and the there the image will be displayed.
the images have the same name as the article-number.
for example: articlenumber is 12345 then the matching image is 12345.jpg.
This works fine as long as the matching image is available.

I hope anyone can help me with this one, i got about 3000 products to
display
and i do not know which product have or have not got an image.
(I also hope i've explained the problem clear enough.)
Thanks in advance for any help and or idea's.

Arthur.