The Poster was published by The Marvin Depreciation Society around 1981. It can be downloaded in several raster formats including PNG (0.8 MBytes), TIFF (1.2 MBytes), PDF (1.5 MBytes), and JPEG (0.3 MBytes). The files are big, containing the same 1890 x 2756 pixel image; it only makes sense to download one.
The original paper poster was 480 x 700 mm and had to be scanned in pieces. If you look hard enough you will see artifacts caused by this process - just ignore them, you ungrateful wretch.
Note that JPEG is a lossy format, so avoid this if you can. The PDF version will print on Letter sized paper.
For those with a technical bent, the various file formats use different compression techniques. JPEG always uses its own lossy compression. (There was a lossless version of JPEG, but it was never widely supported.) PNG always uses LZII compression (also called Zip and Deflate) which is lossless. PDF can use numerous compression techniques; I chose LZII for this file. TIFF can incorporate several different compression techniques; I chose "packbits" (a form of run-length encoding) because it is the only compression technique (for non-binary images) that is part of baseline TIFF, and so guaranteed to be readable by all TIFF readers. Run-length encoding is lossless.
The PNG file is unusually small (820 kBytes) because I ran it through pngout.exe, an optimiser; prior to that it was 1.4 MBytes. Run-length encoding works well on this image (1.2 MBytes) because it happens to contain large blocks of only a few colours, and because I first processed the image to eliminate the noise introduced during scanning. With a more typical image, LZII would compress better than run-length encoding.