The process to insert pictures into your email will depend on what email client/program you are using. You need to first make sure that your email setting is to compose in HTML rather than just plain text. HTML lets you change the text formatting and add images etc. If you can use bold and change your text colors then you are set to use HTML already.
For most programs you can copy the picture from a document or website and then paste it into the body of the message just as if you were pasting an image into a Word document. If you want to add a picture from a file such as a picture that you have on your computer look for an option to insert an image. The name of this feature will vary depending on your program but most of the time will be called insert. It could also be called import. Then you browse to where your picture is located and select it and it will be inserted into the email where you have the cursor positioned.