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 but only one side works and I don't know how to trim the pic minimally to get the other side.

Do a search for aspect ratios above on the search box.

Depending on what format you have originally, likely 2/3 or 3/4 your going to have to do a bit of cropping to get it to 5 x 7. In CS3 do this: Click on the cropping symbol. Across the top of the screen you will have width and height with blank spaces. Just fill in 5 and 7. Then you can crop and it will keep the 5x7 ratio. You can move the box around to get the crop you want. No real need to do anything else unless you want to down sample the photo. If you want to keep the whole photo with no cropping skip the above and add some canvas to the photo.