Ok
Yes I have other back up of my photos on seperate hard drive and aslo have timemachine backing up iphoto as well.
I have tried all the possible fixes you good people have given two or three times. They seem to work untill iphoto is closed and reopened and then the problem returns. it only affects photos which have been worked on in elements lately. Previous photos worked on in elements are not affected, untill they are processes again in elements.
I have iphoto set to use elements as the photo editor and move photos into elements by right click and choose edit in external editor. This opens elements and loads the photo. When work id finished I click save and the photo goes back to iphoto in jpeg largest file size.
On double clicking thumbnail in iphoto to open the photo I get a mega zoom sized picture even in full screen you cannot see the whole picture. If however I swipe the photo untill the next photo in the event is displayed and then swipe back the picture returns to normal size.
This has only happened since I upgraded to iphoto 9.4.2, is it possible to regress to 9.4.1?
My concern on loseing photos is, I think, more a fear that as its running at present iphoto may do somthing to corrupt the images.
When I used the rebuild thumpnails option the problem went away but when I closed iphoto a message displayed saying updating libary and lo and behold on reopening the problem was back.
Photos displayed in other programmes such as keynote etc open correctly I must admit I haven't tried to print any yet to see what size they would turn out.
I appriciate your help and views