When creating a signature it is generally best to keep it as short as possible.
Disclaimers & confidentiality notices in emails are generally regarded as having little or no legal significance, so lengthy signatures just use up bandwidth.
In your country there may be legal requirements for email footers. For instance in the UK if you are a limited company you must put your company registration number and other information in the footer (Out-Law)
Placing images in signatures can be very annoying for the recipient. This especially applies if you embed the image in the email itself, as that means that the recipient must download the image. We have seen cases where the signature contains images of 200kB - which are only of vanity purposes for the sender; the recipient does not want to see those images. Remember the recipient may be reading your email on a mobile device with slow Internet speeds and a usage limit (or paying per MB), so don't fill it up with unnecessary images! Only include images if the recipient will want to see them, or you don't mind annoying them and costing them money.
If you MUST include an image in the signature, then you should link to an image on your website rather than embedding the image in the email itself. This gives the recipient's email client the option of whether to download the image or not (eg on mobile devices). Because of this, the signature facility built into VPOP3 will only let you link to an external image, rather than embedding it in the message itself. Big companies such as Amazon, eBay etc, will all link to images on their site rather than embedding them in their messages, so this is not anything unusual.
Also, including images in email signatures will often make them more likely to be caught by spam filters.