How to search pictures?

How to add music video?

How to edit pictures?

How to use my own pictures?

You can upload your images to Flickr.com as a public image, then you can search by your Flickr user name when you search for images in this site.

Why the card is still small even after I maximized the window?

You can try refresh the browser after you maximize the window. If it is still small, the card might be created as a samll card.

How can I send the card to many friends at one time? Will they see each other's email?

For your convenience, you can send the card to multiple recipients at one time. You can do so by typing in multiple email addresses seperated by semicolon.
For your friend's privacy, each recipient will only see the card was sent to him/her. They won't see other's email address in the cc line.