To insert a picture into the topic you need a link so you can either use an image hosting website like photobucket or if you dont have one click the button above the comment box. If you hover above the boxes you are looking for the box that pops up saying "Host an image"
Click that box and it will open up a box which you can upload an image from your computer and produce you with an image link. Copy the link you require (usually the bottom one) then click the next button to the right and paste the link into the box then hit OK.