Hi. The max resolution on that camera seem to be 5288 x 3506. By S3 you must have added the 9 by mistake as like you know it is 720x480.
What you need to understand here is the concept of dpi: https://en.wikipedia.org/wiki/Dots_per_inch
The size of the printed image can be the same but then the quality of the picture will be lower. If you then want to keep the same quality (same dpi) the S3 will indeed be printed a lot smaller.
There is also a small difference in the ratio x/y (the max resolution is 1.41 while the S2 is i.5). That mean that if you try to print both at the exact same size, two of the sides will never match perfectly.