Image resizing before storing on file system

My application is successfully storing user uploaded image on a file system. Before storing the image I want to,

1. Change dimension of the image so that all images presented to user are consistent in size
2. Reduce image size to lets say 500kb

Can someone please suggest the best way to achieve this or provide any reference?

Thanks in advance

sachin pachpute wrote:
Can someone please suggest the best way to achieve this or provide any reference?

http://www.lmgtfy.com?q=java+image+size
http://www.mkyong.com/java/how-to-resize-an-image-in-java/