Protected/Encrypted Signature for email?


New Email
Hi everyone, my organization uses pre-fixed signatures for all of our employees for emails; something like this:

John Doe, President
(123) 456-7890
{and then here's an image, logo type}

My problem is that the image^ always comes through as an attachment; some email servers don't even show the image.
I've seen that bigger organizations and junk mail usually has a protected (as in you can't click it and save) image, one that doesn't show as an attachment to the email as well.
Everyone I've talked to says it's a mail/computer problem, but I'm thinking there must be a service/business that does this for ppl/orgs. Maybe I just don't know the right word to search for on google lol.
Does anyone know how I can fix this, or some service that could help me fix it?
Thanks I'd be eternally grateful if I could fix this problem, it's these little things that really frustrate an organization; plus we just don't look professional like that.


New Email
The signatures are normally a function of your email client. Your mail message itself must be an HTML message and must be rendered as HTML for this image to show. You can attach this image in two different ways one is to link an image on your website, and another one is still attached the image as a MIME encoded part of a "multipart" document. Both have advantages and drawbacks, for example, if you attach an image from the website, most mail clients set up by default to block any images.
You probably saw it a few times when images become holes in your HTML document with little X marks on them. However, email message itself is still pretty small.
If you attach the image as MIME part of a "multipart" document most of the time your image will show up since it's already there, but each of your messages will be larger so even if you send just two lines your message will be at least a few kilobytes long and in this case it is very advisable to compress your image as much as you possibly can.

Most mail clients will allow you to create a signature within the mail client, and usually it's going to be quite right. The only thing you have to watch out is when you do it in Microsoft outlook, especially if it's set to "rich text format" message type.
The Outlook sends a plaintext message plus some winmail.dat file that is only readable by another instance of Microsoft Outlook, and that is where your problem might be so in this case you have another solution to switch it to HTML.