Hi! So you'll need to use the [img] tags, which you can do manually or there should be a button with a little image icon which will prompt you to input an image URL. I usually take all my sprites from here:
http://www.serebii.net/pokedex-xy/
Basically, click on the Ice-type icon, scroll down to the Pokémon you're looking for, right click on the sprite which will be on the right and select copy image URL. Paste that into either the box that comes up when you click the icon or in between the [img] tags.
Hopefully this is helpful. If you're still stuck, I should be able to give you a little better picture of it.