there is no copyright mark on the image so i assume it is ok to use?
No, that's not true at all! Everything technically belongs to the person who created it -- in the case of artwork, the artist. Putting a copyright mark on something is meant to give strength to any legal claims, should it become necessary. But the absence of a copyright mark does not change the fact that the artist owns the work they created. At least that's my understanding of copyright, as I've learned from personal research. Here are some links to info that I've found helpful regarding copyright.
http://www.copyright.gov/title17/http://www.wipo.int/copyright/en/http://www.publicknowledge.org/issues/copyrightIf you really, really want to try and find the artist, you might try googling the username. Maybe they use it in other forums, where maybe they have an updated registration email? Also, a lot of artists use sites like DeviantArt, Flickr, etc. to display their work. You could search some of those as well. Even search here for other images jude might have posted -- if they use DA, etc., there may be a direct link from another image. Just a couple of thoughts.
Good luck

Edit -- PS - I did a little searching myself, and found that jude has a website, with a tutorial for the dandelion image:
http://hereshowididit.com/something-ive ... orking-on/ You could draw your own!