Post the pics on photobucket first. Then click on the little mountain clip-art thing in the post box and enter the "direct link" you see under the photo on the photobucket page. The other pic is on the profile page, edit avatar, make sure its under 140x140 pixels.
You can simply attach photos in low resolution (ie: 4x6 @100dpi) using the "manage attachments icon on the reply to thread or New thread link on this site. Look directly below the text box at the options Below:alcy:
Or to get all technical and webby about it.... use tags! Upload the image to a host somewhere like Photobucket or Picassa. Find the url for the image - looks like a web address ending in a pic file format like .jpg or .gif. Copy the url and paste it into your post. At the beginning of it, start with as the beginning of the image - called a tag. At the end, write the same thing but put a "/" before "img". The program will recognize the url as an image instead of a link and you'll be all set!
By the by, can't explain the end tag by just writing it as [/whatever] because it'll trick the programming into thinking that all the text I wrote is an image url. Go figure! lol