Well you can easily transfer your contacts and photos to your samsung galaxy s3. You need to some simple steps to transfer your files and contacts on your phone. Before we proceed, I will strongly recommend you to take the backup of your data and save in your Itunes. Follow the below steps.
1. Open Samsung Kies, connect your Samsung Galaxy S3 and stay connected.
2. Now goto main page where you can find option basic summary select it.
3. Now you can see on the screen option to 'Transfer your BackUp data from Non-Samsung Device'. You need to select iPhone backup. Now you just need to select the files & contacts which you want to transfer to your samsung galaxy s3.