Pictures not loading properly in iPhoto/full screen

Question

Hello
When I try to view a picture in full screen, or if I try to edit a picture, it appears to load properly at first, but then, after a few seconds, parts of the picture disappear to be replaced by large, black rectangles. I'm running iPhoto 9 in Mavericks.
To clarify, my iMac has only 2 GB RAM and the photos are RAW images, so typically between 10-15 MB each. This has always meant that they have taken a little while to appear in full resolution. Generally, when loading an image in full screen, a complete but fuzzy image would appear for a few seconds then suddenly spring to sharp, full resolution life. This is the point at which things now go wrong. Instead of the full resolution version appearing in sharp clarity, parts of the picture are replaced with large areas of black nothingness.
Any help gratefully received.
Cheers
Dave

Answer 1

If it worked OK in the test library give this a try:
Starting 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. Open the library package like this.
2. Launch iPhoto with the Option key held down and, when asked, select the option to create a new library.
3. Drag the subfolders of the Originals (iPhoto 09 and earlier) or the Masters (iPhoto 11) folder from the open iPhoto Library package into the open iPhoto window a few at a time.
This will create a new library with the same Events (but not necessarily the same Event names) as the original library but will not keep the metadata, albums, books slideshows and other projects.
Note:  your current library will be left untouched for further attempts at a fix if so desired.
OT