Provide user an optimized image for printing

[skunark]

It would be cool to provide the user with an optimized image for printing.   I believe 300 dpi is ideal for most photo printers that claim 4800x2400 resolution, but adjustments might be required based on the user's printer.

The advantages could be:
*Saving Network Bandwidth: A smaller file will be used to transfer the image over the Internet when compared to the full size original image.  i.e. Convert a 2048x3072@180 dpi image to a 4x6 1200x1800@@300 dpi would reduce the file size about 50% and provide a better image for the printer.
*Enhancing the User's experience: Multiple files could be created for an image for different print sizes i.e 4x6, 4x8, 6x8, 8x10 etc and all at 300dpi for enhancing the user's coppermine experience.   
*Enhancing the Print Quaility: Multiple photo magazines actually encourage you to change the resolution of the image to 300 dpi before sending it to the printe.  I assume the printer's (or the printer driver's) ability to render the image isn't as good as software found in PhotoShop or Gimp.
*Room for other options: Also could be a stepping stone to provide the owner of the image a standard method to apply a boarder, watermark and/or logo to the image.

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Jim