When printing 6 x 4s at my local photographic shop, what is the minimum resolution I should supply to avoid loss of detail?

My 3yo Casio Exilim EX-Z40 camera stores at around 1.72 MB (best resolution), which I normally supply.

Need to know how many I can cram on a 700 MB CD for mailing to a friend to print off. Thanks.

Stick with the highest resolution and quality that the camera can do, you won't regret it.

If the files don't fit on one disk, send two

Megapixels don't mean everything. It also depends on the quality of the camera, the conditions the picture was taken in, and the ability of the photographer. Also post-processing (such as a simple unsharp mask) can help a *lot*. But generally, a 4x6" print will require something along the lines of a 2 megapixel image to look OK to the casual viewer.

But what Crossy says makes sense, just send the originals, taken at the best (or nearly the best, you usually don't need the "superfine" or "best-best-super-duper" quality, just the "fine" quality, since they're basically indistinguishable) quality. They offer the most data for the shop to process.

The general standard for high quality printing is 300dpi resolution. So to print really clearly at 6 x 4 (inches?) your photo also needs to be 1,800 x 1,200 pixels.

You can go lower than this, but it become progressively less sharp. A lot of 'photo software' and also Vista seem to think that, when it comes to printing, having a small file size is far more important than having a picture that looks good.

1800 x 1200 is 2.16 MB. So at my max resolution of 1.72 MB I'm still 20% down on optimal. Camera is only 3 Mpixel.

Thanks for the replies!