Nikon d40 6mp camera.resize images larger?

I was putting some pics on red bubble and the the only size i could sell was a small (11x8) my images are 3008x2000 and thats the largest setting…

how large can i resize it in photoshop and it still be good quality?

Added (1). Also what size of the actual photo can i do? Ex 12x16… 20x30 etc

ANY time you resize or resample an image to a larger resolution you will lose quality. It's going to pixelate the image. The rule is, you can always resize down but resizing up will cause image quality loss. Even the best Photoshop plugins for this don't work very well. At 12X16, your image will look just fine at 3008 X 2000 resolution. Going to 24 X 32 though, you'll see some image quality loss, but an image that large isn't viewed at up close, it's viewed from a distance and the quality loss on that will be negligible.

A reasonable 20 x 30 should be possible but will usually involve a lot of photoshop tweaks, such as pumping up the resolution, extra sharpening etc.

You could start with a resolution setting of anything between 400 and 600 dpi and resize your pic to 20 x 30. Photoshop will then extrapolate and add the extra pixels beyond the native resolution of your photo. Check the result on your screen, sharpen as necessary, and play around with brightness and contrast curves. In some instances however, an enlargement can be impoved by using one of the blurring tools, believe it or not. Of course, you'll need a good, sharp and contrasty photo to begin with as this process will test the inherent quality of your image to the limit. Shooting in RAW (.nef files) is always a good idea if quality is what you want.

Another approach would be using a dedicated software package (see links below) such as Benvista PhotoZoom Pro (pretty expensive) or Focus Magic.

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