Photos transfer from iPad to Mac, saving all changes?

Only photos in the Camera Roll get transferred between devices. Once added to the iPhoto library on your iPad and edited the edited version is no in the Camera Roll. You need to copy them to the Camera Roll in order to be able to transfer them to your Mac.

To save the edited photos to the Camera Roll, as Old Toad suggested, do this: (iPhoto Help: 2.0 What is iPhoto?)

Save photos to the Camera Roll on your iOS device

1. Tap a photo, album, or event and tap "Share" > Camera Roll.
2. Tap Selected, or change the photos you want to save:
   • Select different photos: Tap Choose Photos, tap up to 100 photos, and tap Next.
   • Select a range of photos: Tap Choose Photos, tap Range, tap the first and last photos in the range, and tap Next.
   • Select all the photos in an album or event: Tap All.
3. Tap Done.

You could also share the Photos using iTunes:

Save photos to your computer using iTunes

• Connect your iOS device to your computer.
• Tap a photo, album, event, web journal, or slideshow and tap "Share" > iTunes.
• Tap Selected, or change the photos you want to save (if you are saving a slideshow skip to step 4):
  • Select different photos: Tap Choose Photos, tap one or more photos, and tap Next.
  • Select a range of photos: Tap Choose Photos, tap Range, tap the first and last photos in the range, and tap Next.
  • Select all the photos in an album or event: Tap All.
• In iTunes, click the button for your device and click Apps at the top of the window.
• Below File Sharing, select iPhoto (in Apps).
• Select the Shared Photos folder under iPhoto Documents.
• Click Save To and select the location on your computer where you want to save the items.