Gmail on the web: Compose a message, and then drag and drop the picture from your computer to the desired position in the email. Or, position the cursor where you want the image to appear, select Insert Photo > Inline, then choose your photo and select Insert.
How do I embed an image in an email?
Position your cursor where you want the image in your message. Select Insert > Pictures. Browse your computer or online file locations for the picture you want to insert. Select the picture, then select Insert.