I happen to own one of the lobby cards so dreadfully scanned by that ebay seller.
I scanned it at different resolutions, the results (uncompressed except for the bmp->jpg conversion) are as follows:
The first image is a 100dpi scan - this was also negatively affected by the jpg compression. The second is a 150dpi scan. Stripes are still there, and show in the jpg very similarly to the bmp. The third is a 200dpi scan, and in this case the stripes are pretty much gone. The last image is a small snippet from a 600dpi scan (a snippet because the full image is 12MB), and here you can see the granularity of the print.