Logo in E-Mail signature does not always work. Have saved it as a .bmp and as a .jpg and it seems to make no difference. Does anyone have any ideas?

I have a similar problem. I have made a html email signature for a client that includes the company logo in .gif format. I've added the signature file and image file to the signature folder in the users document and settings application signature folder. When the suer sends the email it works fine but when a colleague replies the logo is lost and appears as an attachment in the reply. This is the first time i've had to use exchange with html signatures and so i'm not sure if there is a setting on exchange or if it is my signature that needs tweaking. I've also tried using the signature as a stationery type but this also fails. could it just be the image type? any ideas?