To put an image into Dreamweaver you just need make a CSS style for a div and go to background. There you can make it a color or any photo you may have saved. One good way to put things into the background is by creating your image in Photoshop first and then slicing it. This was you can cut the image into different sizes and save your sliced pictures. When you go into Dreamweaver you can put it back together piece by piece. This is really nice for images that you can’t create in Dreamweaver and need the tools of Photoshop to complete.
To slice you just go to your knife icon in your palette and zoom in very close to your picture were you can see every pixel. When you size your div you do so by using pixels so you want to make sure your image is exactly the right size. After slicing over what you want or completing the entire the size of the site you save it. Make sure to save it into your public folder under images so can have it with you whenever your working on them. Then they are ready for use, you can use a few or all of them.