Mail keeps adding spurious PNG attachments

When I reply to an email, Mail keeps adding spurious PNG files to my messages. They definitely aren't there when I hit "send" or when they're in my outbox, but they are attached to the mail before the recipient gets it. Sometimes I see them in my "Sent" file, but not always; usually the recipient cannot open them and often I cannot do so either, but when I can open them they seem to show a graphic related to the business of the original sender of the mail that I am replying to (it doesn't happen if I start a new mail instead of replying to one)

Can anybody explain to me what is going on?

Keeping Up said:

When I reply to an email, Mail keeps adding spurious PNG files to my messages. They definitely aren't there when I hit "send" or when they're in my outbox, but they are attached to the mail before the recipient gets it. Sometimes I see them in my "Sent" file, but not always; usually the recipient cannot open them and often I cannot do so either, but when I can open them they seem to show a graphic related to the business of the original sender of the mail that I am replying to (it doesn't happen if I start a new mail instead of replying to one)

Can anybody explain to me what is going on?

When I see problems with sending or replying or forwarding I add one of my other E-Mail accounts such as Hotmail or Gmail in the BCC block, see if I get what is actually being sent and probably what the other recipient/s get.

Berton said:

When I see problems with sending or replying or forwarding I add one of my other E-Mail accounts such as Hotmail or Gmail in the BCC block, see if I get what is actually being sent and probably what the other recipient/s get.

I've seen some of them in my "sent" box, after the recipients contacted me to say they couldn't open the attachments. The question is, why are they there?

I'm still puzzled about this. After studying the problem, it seems as if when I reply to an email which contained a link to a website (such as a company website that is referenced in their signature) the email client looks on that site and selects a random jpg or img file from that page if it finds one, or selects an area of the page and makes a png image from it. It then attaches that image to the outgoing mail secretly; it doesn't show in the Outbox, nor even in the Sent Mail folder unless you deliberately refresh it. It's rather like the way Facebook attaches an image if you include a link in one of your postings.

The annoying thing is that the image may bear no relationship to the topic of the email, or the file my be unreadable by the recipient (especiaslly if its a png file) or it may be rejected by their firewall because it contains an image.