Your picture of your code didn't come through. You can't link to a picture that's on your computer, as a server on the internet cannot access your computer to display the picture for others to see. You have to upload the picture as an attachment. Then, if you want to actually display the picture in the message you have to edit your post, insert a picture, and when it asks for the URL you enter the URL of the picture. You can get the URL when viewing the message, as the link is within the message itself.
As for your question, can you just use the TypeCast function?