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Attaching a photo file of you would probably be sufficient.
But to make sure it really shows up good, you would want to send a copy to yourself first, with photo attached, to see it as a recipient and make sure it comes across well. (This is not absolute guarantee, since various email packages handle an inline or an attached photo file differently in several different ways.)
What email system are you using, e.g. Outlook, or what email server are you sending from (e.g. Hotmail, AOL, etc.) ?
You can also copy the picture, and paste it into the body of the email as you compose it. It will most likely end up at the bottom, but this may make sure (in some recipient email systems) that it is viewable instantly.
How did you insert the photo file?
Did it show up in the draft of the email, before sending, as a photo?
Oh, that's different. A profile picture? that might show up in some recipient's email systems, yes, and I didn't think of that, I admit.
You are using Outlook.
For other Outlook users, it may show up.
But for different email systems, it has only a very scanty chance, not a certainty, of showing up. This issue has been gone over in Microsoft forums and, basically, there's no way to be certain and sure that your profile picture will show up in association with your email address or your sent emails in a differing email system.
Including an in-line photo in your email body or email message, is far more likely to be seen OK by the recipient.