Use Illustrator to create your logo as a vector graphic and export it to SVG. See Illustrator screenshot.
Once exported, you can re-scale your SVG logo without any loss in quality. You cannot do that with raster images -- JPG or PNG.
Thanks that really helped. And I got to learn a bit of Illustrator.
I made my logo in Illustrator.
Now another question.
I put the SVG file in my site folder in Dreamweaver.
But when I want to place the image I cannot select it.