The problem with most of these online photo editing websites is that your image will be saved out at a drastically lower resolution than when you started.  Typically they will save image at 480px X 640px.  When this is increased to our print area of 17" x 23", your resolution is reduced to about 28 DPI where our suggested minimum is 150.  Printing this sized file would result in significant blurriness and pixelation.

 However, with paid versions of these sites, usually the native resolution of images uploaded is preserved.  Beware of these sites and remember if you have a question, please ask us first!