Back story: I took a picture of a flower in RAW. Pulled it into ACR in PSE 12, moved it to the Photoshop Elements editor, made a few edits, then saved it as a "small" JPEG. When saving a pic in PSE, there is a "JPEG Options" dialog box that comes up and gives you the option to choose the quality of the saved image. You can Choose from a sliding scale from 0 ("small" or low quality) to 12 ("large" or maximum quality). For this one flower pic, I choose a relatively small number b/c I only intended to post online for viewing (4 I think). My wife saw the pic, loved it, and now wants me to blow it up, put it on a canvas, and put it up in the guest bedroom! I go to my favorite printing site, upload the pic for the canvas print, and the site says "can't print at that picture size because your image is too small."
I want to the best quality image for canvas print enlargement.
Question: If I simply re-open the current pic, do no edits, and re-save it in PSE at the "12/large" size setting in the JPEG Options dialog, will the image quality re substantially reduced - making it not good for enlargement? This seems the simplest route to go, but I have a sneaky feeling that re-saving an image that was saved as "small" to a larger size is making a sandwich with "used" bread. Other option is to start with the RAW image again, re-do the same edits and save a new JPEG at the large size setting. Looking for some expert experience/advice on whether there is any real noticable difference btwn these two options in creating a larger sized image suitable for the canvas enlargement.