Update megapix-image.js
Update megapix-image.js

resolve issue 17 (https://github.com/stomita/ios-imagefile-megapixel/issues/17)
yinsu/ios-imagefile-megapixel,yalishizhude/ios-imagefile-megapixel,stomita/ios-imagefile-megapixel,stomita/ios-imagefile-megapixel,yalishizhude/ios-imagefile-megapixel,yinsu/ios-imagefile-megapixel