I post all of them on my blog! They are my favorite collection.
Download from my blog: http://galaxyswallpaper.blogspot.com/

https://lh4.googleusercontent.com/_G8_zs6DJsUA/TWOEKmTysfI/AAAAAAAAAVI/7-2ZyRc1CFg/s576/galaxyswallpaper.blogspot.com.jpg

https://lh3.googleusercontent.com/_G8_zs6DJsUA/TWOFAVHGn_I/AAAAAAAAAVY/aoYJxxr6QfU/s576/galaxyswallpaper.blogspot.com%20-%203.jpg

https://lh3.googleusercontent.com/_G8_zs6DJsUA/TWOFAD-7KJI/AAAAAAAAAVU/uJGibtv4Uy4/s576/galaxyswallpaper.blogspot.com%20-2.jpg

I collected all of them carefully. Only the best one will be chosen.

Although the Ubuntu Girl can come round any time, the image size seems to be 547x455 for all the images I looked at.

I seem to recall the screen resolution not being that.

just click on every image on this site, you will get the hight quality image, and save as... on your computer. good luck!