PART I
This will not work with photos on your home computer!
If you host them on a free host, all you need to do is get the address of the picture and paste it in the message box. This can usually be done by right clicking the picture. You should also be able to copy the url from the info box next to the picture. Understand that there might be a limit on the bandwidth you get each month.
This method will also work to show picture from other websites.
Right click the photo for this,

Then select properties to get this,

Then copy the Address (url),

Then paste the code into your post,

Then hit submit,
