i have lost my photos/videos when i imported from my ipad 2 to my new imac latest version and it's not reading the files. I have downloaded iMac library manager and can see them. can someone shed some light please ?

Hold down the Option key and launch iPhoto. In the window that comes up do you see more than one library? If so open each one in turn to see which is your full library. Also note where each library is located.

OT

So it appears you have only one library on the hard drive. Apply the two fixes below in order as needed to that library:

Fix #1

1 - launch iPhoto with the Command+Option keys held down and rebuild the library.

2 - run Option #4 to rebuild the database.

Fix #2

Using iPhoto Library Manager to Rebuild Your iPhoto Library

1 - download iPhoto Library Manager and launch.

2 - click on the Add Library button and select the library you want to add in the selection window..

3 - Now that the library is listed in the left hand pane of iPLM, click on your library and go to the Library ➙ Rebuild Library menu option.

4 - In the next window name the new library and select the location you want it to be placed.

5 - 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. However, books, calendars, cards and slideshows will be lost. The original library will be left untouched for further attempts at fixing the problem or in case the rebuilt library is not satisfactory.