I figured out how they decide which ones get on their home page. There is a page where you can vote on the different ones the ones with the most votes get on. I uploaded and made my first LOL today!
Couple ways.
* Save the pics to your PC and then upload to a photo-stashing site like photobucket.com. Then link it from there.
* In the site itself right click on the picture you want. Then click on 'properties'. Highlight the 'Address:' with your pointer. Right click then 'copy'. Come back here and click on the insert image icon. Delete the 'http://' that's already there. Right click in the space. Click on 'paste'. Done. Clear as mud?