Sorry I didn't explain correctly. Iexported all the events (one by one) and then I erased all of them (one by one). Any time I did clean the trash I could see how the size of library was getting down. Curiously at then end of exporting and erasing all photos I still have a library with a size of 38 gigas. In iPhoto I can see 0 event 0 photos and 0 albums and so on.
How can I check what is still using those 38 gigas? or Why the library is so big even in the case that I have cero (0) photos stored?
thanks in advance for your help