[Thanasis Papadimitriou]

It doesn’t matter and you shouldn’t resample your image back to 300dpi. There is no problem with more dpi. Magazine or books editions use publishing/layout programs like InDesign, QuarkXpress etc. The layout designer will scale your photo to fix in the magazine, newspaper, brochure etc page in one of these programs. Commercial printing companies need 300dpi (CMYK mode) images for high quality prints so even if you give them a 1000 dpi RGB image you’ll get a 300dpi CMYK brochure, magazine etc. (Keep in mind to check your images in CMYK mode to see the colors you will get in the final print.)

[Thanasis Papadimitriou]

Yes resampling is going to reduce the quality of the print.
If you want NO quality loss and your original image is 8*12 in 240dpi you have to print it in 9.5*6.5 in 300dpi.
Βut my personal opinion is that human eye cannot understand such a difference.
Image size > uncheck “resample image” > set your size in resolution >
check AGAIN “resample image” > OK

These all have to do with offset printing. for laser/inkjet printers things are easier.
Sorry for my english -I’m a greek.

[Thanasis Papadimitriou]

just in case you need an answer right now: 240dpi is excellent for commercial printing. i’m a pro graphic designer and i had to use images of less than 300dpi many times. if you have to use an image of 240 dpi for a flyer, magazine or a newspaper there will be NO problem.