Secure and "squarified" photo uploading in ASP.NET MVC

I'm building a website for a club, and I'd like each member to be able to upload a profile photo.

I've seen a few questions and answers on SO about the basics of how to do this, but I'm concerned about two things that are a little bit more challenging:

1. Security - I want to prevent people from uploading files that are not valid images and/or c开发者_如何学Pythonontain malicious content.

2. Uniformity - I want files to be of a reasonable size and images to be square. I would like to provide a UI to help the user crop the photo into a square once the photo has been uploaded and verified.

Ideally, I'd like to find a free/open-source utility that I can just plug in to my app and go. If there's nothing like that available, I'd appreciate advice and/or sample code.

I don't think there is any plug-in utility to help you. Best would be to just build something yourself. Here are two blog articles that could help you to easily create your own validator:

• How to Securely Verify and Validate Image Uploads in ASP.NET and ASP.NET MVC
• Image Upload & Validation with ASP.NET MVC 3
• Image Upload, Crop and Resize with ASP.NET MVC jQuery Uploadify and jCrop