I wanted to place one of the drawings as desktop background, but to make it seamlessly integrate (not to look so ugly as in the post). Looking for solution, I stumbled into one very effective filter in Photoshop CS (not sure is this included in earlier versions).
Load the image into Photoshop
Go to Layer / New Adjustment Layer… / Photo filter…, leave all default in first dialog
In the filter dialog, set the options as shown (click to see it with preview), and pick your desktop background color.
And this is the net result - nice and unobtrusive, just as I like it. :)