If you're talking about iCloud photo library, iPhoto does not support that, and cannot upload photos to it. Also, Apple has not yet provided the ability to upload photos to your iPhoto library by dragging and dropping them to your photos at iCloud.com yet (although it's been reported that they are starting to work with this on their beta site; see http://9to5mac.com/2014/11/06/icloud-photos-beta-upload/).
At the present time, you can only get them to iCloud photo library by adding them to a shared photo stream in iPhoto (see http://help.apple.com/iphoto/mac/9.6/#/phtf7fe6394), then opening the shared album on one of your iOS devices and saving the images to your device (tap Select, tap the images, tap the share icon, then tap Save Image). They should then automatically be added to your iCloud photo library.