서버에서 image 인지 체크, image 크기 체크

< Test if file is an image >

http://stackoverflow.com/questions/9643228/test-if-file-is-an-image

< How to check a uploaded file whether it is a image or other file? >

http://stackoverflow.com/questions/4169713/how-to-check-a-uploaded-file-whether-it-is-a-image-or-other-file

< How to get image height and width using java? >

http://stackoverflow.com/questions/672916/how-to-get-image-height-and-width-using-java