Any visible creases in the image existed in the original poster I used; I scanned the large original in six separate scans and then collated them to produce this electronic image.
These files are large because, to preserve clarity of the font, I had to use high resolution and high image quality.
If you open these images in a browser, the lower-resolution images will appear smaller than the higher-resolution ones, even though their actual width when printed might be identical. This is because a browser, unlike a graphical application or a printer, will display each pixel of the file on one pixel of the screen, hence making it appear larger.