It appears that the library that you restored was damaged in that it was missing 600 pictures. Try this: launch iPhoto with the Option key held down to create a new, test library. Import some photos into it to see if they end up blank. If not then your current library is damaged.
If that's the case make a temporary, duplicate copy of the library and try the three fixes below in order as needed:
Fix #1
1 - delete the iPhoto preference file, com.apple.iPhoto.plist, that resides in your Home/Library/Preferences folder.
2 - delete iPhoto's cache files that are located in your Home/Library/Caches/com.apple.iPhoto folder.
3 - reboot, launch iPhoto and try again.
NOTE: If you're moved your library from its default location in your Home/Pictures folder you will have to point iPhoto to its new location when you next open iPhoto by holding the the Option key. You'll also have to reset the iPhoto's various preferences.
Fix #2
Launch iPhoto with the Command+Option keys depressed and follow the instructions to rebuild the library.
Select the options identified in the screenshot.
Fix #3
Using iPhoto Library Manager to Rebuild Your iPhoto Library
Download iPhoto Library Manager and launch.
Click on the Add Library button, navigate to your Home/Pictures folder and select your iPhoto Library folder.
Now that the library is listed in the left hand pane of iPLM, click on your library and go to the File ➙ Rebuild Library menu option
In the next window name the new library and select the location you want it to be placed.
Click on the Create button.
Note: This creates a new library based on the LIbraryData.xml file in the library and will recover Events, Albums, keywords, titles and comments but not books, calendars or slideshows. The original library will be left untouched for further attempts at fixing the problem or in case the rebuilt library is not satisfactory.
If none of these fix the problem this is your next step:
Start over from scratch with new library
Start over with a new library and import the Originals (iPhoto 09 and earlier) or the Masters (iPhoto 11) folder from your original library as follows:
1. Move the existing library folder to the desktop.
2. Open the library package like this.
Click to view full size
3. Launch iPhoto and, when asked, select the option to create a new library.
4. Drag the Origianls (iPhoto 09 and earlier) or the Masters (iPhoto 11) folder from the iPhoto Library on the desktop into the open iPhoto window.
Click to view full size
This will create a new library with the same Events as the original library but will not keep the metadata, albums, books slideshows and other projects. Your current library will still be available for further testing if desired.