thank you for the clear explanation.I know the logic now.
My configuration:
Small w75* h88
Medium w360*h420
Large w514*h600
*all the three proportion is 75:88=360:420=514:600=6:7
the image original size w600*700.
After it is uploaded by AIS, the 3 sizes are below:
Small w64* h88
Medium w308*h420
Large w514*h600
now we should know the problem. the proportion cannt be kept at smal size and medium size.
You can click here to see the wrong operation now :
http://www.he15.com/index.php?main_p...products_id=76