Right click the ones you want and then click "Save As." Make sure they go into a directory where you know you can find them later. To post them here on the forums, you can use imageshack.us or photobucket.com (or any image hosting site of your choice).

From Photobucket

Click on "Browse" and locate your picture, then click "Upload it." On the new page, scroll down to your image and left click to select the entire "HTML Tag" line, then right click to select "Copy." Paste it directly into your message box.

From Imageshack

Click on "Browse" and locate your picture, then click "host it!" On the new page, scroll down to the line that begins with {{!gwi}}

{{!gwi}}{{!gwi}}

{{!gwi}}{{!gwi}}

{{!gwi}}{{!gwi}}

{{!gwi}}

{{!gwi}}

{{!gwi}}{{!gwi}}

{{!gwi}}

{{!gwi}}

{{!gwi}}

{{!gwi}}