The above image is a vector drawn image (though some machines may
display two images). Vector images have the advantage that
you can enlarge them as much as you want and it won't pixellate.
But the image below this is a bit-image, made up of pixels. If you enlarge this page, the pixels below change to blurred small blocks of colour. This is how bit-images are made and this effect is called pixellation.
Vector images therefore give better clarity on the web. They have been around since 2001. But not all browsers handle them well. Currently (2015) the Firefox browser for Mac desktop machines has problems with some files.
I have removed the features from my images that give Firefox this problem. But there could be other problems that other browsers show with SVG files. Please let me know and, in the meantime, try another browser: Safari and Chrome both work OK (so far) as does Internet Explorer on a Windows based SmartPhone.