You can configure Outlook.com to automatically block attachments, pictures and URLS from unknow senders. It should be noted that once this option is activated, you'll only be able to access above-mentioned items from contacts from your safe sender list only.
To enable this option, from your Outlook.com home screen:
Click on Settings > More Mail settings.
Go to Preventing junk email > Filters and reporting
For the "Block content from unknown senders" option, select:
Block attachments, pictues, and links for anyone not in my safe senders list".