i posted to the microsoft outlook group and this is the reply i got from an
admin (ignore the lesson in etiquette):

loki wrote:

i've created a signature which is our company logo with details.
sometimes it doesn't display for the recipient.

i created the gif, then created an .html file with that .gif in it,
then loaded both to my server. then created the signature by
selecting the .html file
is this something i can fix or is it dependent on their email client
settings?

First, the recipient's mail client must support the interpretation and rendering
of any code you've included in the signature. Not all clients do. Second, their
client must support the displaying of any graphics you've included. Third, the
recipient must have configured the client to enable this support if it's
available. In short, you can't control with certainty how the recipient sees
your message. My opinion is that best practice calls for using the most common
sending format: plain text. The purpose of email is to convey information. It
is rare indeed when a company logo conveys information the name and address of
the company do not. Moreover, graphics add to message's size, often doubling it
without increasing the amount of information conveyed. That's poor use of a
communication medium. Finally, if information exchange can be enhanced by the
inclusion of graphics, it's better to include them in an attached document that
also explains the context of the graphical information.
--
Brian Tillman