Alrighty, I'll try my best to explain.

First, you should have some sort of photograph or, more preferably, a scan, of the actual picture, if done traditionally and not digitally. Then, you should upload it to some sort of website; I say Imgur's easiest, which is the option I'll be explaining. On the header of Imgur is a button with an icon and an arrow which you click in order to upload your image. Once you upload it to Imgur, you should be directed to a page upon where, to the right side of the screen, there should be a bunch of links with the following labels: Image Link (email & IM), Direct Link (email & IM), Markdown Link (reddit comments), and so on. Copy and past the link under Direct Link, and then paste it in between this code: (img) (/img)
Just be sure to replace the '(' with '[' and the ')' with ']'. I had to type it with these brackets as otherwise they wouldn't appear.

Hope that helped. At the very least, hope it doesn't seem too complicated.