No doubt I am a learning amateur photog! :) I have a couple galleries up now, and listed low resolution digital downloads for sale. Now I am questioning if they are truly low res, and can't remember how I came to that conclusion in the first place. I edit everything to 300 dpi, which i have read is high res. Smugmug's determination is low res is 1 mpix or less. Not sure if I'm on the right track with this formula I found, but my edited 4x6's are 1800x1200 pixels, which when divided by 1,000,000, equals 2.16 mpix and again would be high res. Sorry to ask what I'm sure is a simple question, but trying to get things right and learn. Thanks!
Don't change the resolution at all. Upload your original full-sized images from your camera. Don't resize, don't change the pixel dimensions. SmugMug automatically makes 8 display copies, from tiny thumbnails up to 1600 pixel X3 size. When you order prints, SmugMug will use your Original image, which will have all of the original pixels. When someone buys digital downloads, SmugMug will automatically make Web Size, 1 Megapixel or 4 Megapixel files from your Original image.