[Clipart] OT: large high-resolution images for printing large?

[Jeremy C. Reed]

Off-topic ...

1) Does anyone know of any download sites that have large high-resolution 
public domain images that can be used for printing large format?

I can only think of NASA images, but I am also looking for historical 
paintings, etc.

2) What are your experiences with blowing up images made for web onto 
large format? Any formula for figuring it out? For example, I have a 
1600x1190 JPEG (quality 92) from NASA that is 300x300 pixels per inch that 
I'd like to have printed (at a photo center) at around 24 inches by 18 
inches. That seems like it will work out, but stretched out that is less 
that 65 pixels per inch.

I also have smaller around 523x595 JPEGs (quality 90) also at 300x300 
pixels per inch that I'd like to have printed large, but maybe that won't 
work because I think when stretched out that is less than 22 pixels per 
inch. And that is why I want to find public domain sources of large high 
resolution images.


  Jeremy C. Reed