Let me see if I understand, someone sends you an email with an attachment, the you open it with corel in order to view it. If this is the case this is how attachments work, they do not automatically open when you recieve email, You have to double click the attachment and choose the program to open it with. It is attached to the email not a part of the body of the email. I hope I understand your issue correctly and have not wasted your time again this sounds like default behaviour for attachments.
How e-mail attachments are shown depends among other things on the e-mail software used for both send and receive the messages.
For example, in Outlook, you can add a picture attachment to an e-mail in two ways: You can use the 'Attach' option, or you can use the 'Insert->Image' option. If you use the attach option, the image will be sent as an 'external' attachment, but using the second option, the image will be sent as part of the e-mail body (in-line), and the recipient will <i>probably</i> see it without the need to click on the attachment.
On the other hand, e-mail programs may treat incoming e-mail attachments in different ways. Some of them will include image <b>attachments</b> at the end of the e-mail body, even when they are not part of the e-mail body, but some other e-mail programs won't.
Another reason for this behavior is that you have a wrong default file association for the images so they will actually try and be seen in Corel; in order to fix this right click any image in your computer and choose "open with", the select the Microsoft image viewer and check the options "always use this program..."
Sometimes Outlook doesn't show pictures from contacts "not marked as safe senders" and this has another behavior where you see the body with no images at all and have to click on the bar that appears notifying you this .