Can someone help me. I have tried to resize some of my photos in PS3 but it doesn't fit the dimensions exactly. How can I re size my photo to look as close as possible to the original for print. I want to print some 5 x 7 pics- I changed the DPI to 250 and tried to change the side to 1250 x 1750...

One of my customers wants a 3 x 3 print for a frame she has. I noticed that Mpix does not have 3 x 3. Does anyone have anysuggestions for me as to how to get her the 3x3 print she desires? I have thought about doing a 3.5 x 5 or a 5 x 5 and then cutting it to size but wasn't sure if there was a more...