This is a massive Starship Size Comparison Chart, created by designer Dirk Loechel and posted on DeviantArt.
The design gathers ships from many different science fiction movies, tv shows and games, and sizes them down to a common scale so viewers can grasp the relative size of how large and small the ships they recognize are.
As this get shared heavily online, it would be nice to have the URL back to the original, full-size version included in the design.
I love this size comparison design! The subtitle mentions that Dirk's design is "based on the work of others" A much smaller Starship Size Comparison Chart was one of the first posts on Cool Infographics back in July of 2007, and that version is no longer available online.
Thanks to Mary Kaye for sending me the link!