I think those instructions are for sizing an avatar...
If you want to post pictures...first upload them to a server like photobucket...this is what I use and it VERY easy...upload a picture and then click save to album...
once that is done...drag your mouse over the pic and a drop down selection will appear...on my computer all I have to do is click on the URL code and it is "copied"...you might have to right click with your mouse to get the "copy" prompt...once the image is "copied"...go to OG and then paste on your topic thread...thats all there is to it...
Good luck and lets see them pics!!!