Q: Download iPhoto from my account on my mac

Because iOS and Mac OS X are separate platforms. The developers need to write their applications separately for both, and may choose to charge for both versions.

(110480)

iPhoto on your iPad is a completely different program from iPhoto on your MacBook. It cannot run on Mac, because it requires a different operating system and a different hardware. The programs only share the names.

You will have to buy iPhoto '11, version 9.5.1 to use on your MacBook.

contact App store support - that does not involve iPhoto

The support link is on the right side of the App store window

LN

thank you .. now I can't purchase i forget my security questions , what can I do ?

Have you set up a rescue email?  Then try the methods described here in this link:  Apple ID: All about Apple ID security questions

If that is impossible for some reason, you need to give Apple Support a call - only they will be able to help you. See this webpage on how to contact Apple Support in your country: There are either telephone numbers given or an email form:

     Apple ID: Contacting Apple for help with Apple ID account security

When you give them a call, explain, that you need help with an account security problem. You need to speak to the account security team.