This RAR contains categorized GIFs, which are based on a shoddy PDF that was floating around (it was the best scan available online as of 2011).

The JPGs in the PDF were extracted, and converted to optimized GIF (original quality was fully preserved by a perceptual palette selection in PS).

At this time I don't know of a higher resolution scan of the complete Calvin and Hobbes. Only a 600 dpi scan would do justice to Watterson's masterful sable-brush strokes.

If you like Watterson's work, please consider buying this: https://www.amazon.com/Complete-Calvin-Hobbes-v/dp/0740748475

It's completely worth it - beautiful quality!.