Setting up signature image and image is received blurry

[Beesoy06]

Hi,
We've been asked to set up signatures for our staff email. We have a perfectly good 96dpi image that we are using. It looks great in the signature field when typing up your email etc. However the recipient gets a blurry, pixelated image in the signature field.

I've tried everything I've read in the other forums (e.g. edit the htm file and resize to 600x200, etc) but this is stumping me. How do we get Outlook not to change the format of the stationery image?