Just another small point. I had a single sim on a 60x60 lot and spent ages turning it into a super floral park. I put the ground cover over every flowerbed, then lots of flowers, shrubs, trees, rocks and sculptures. It looked lovely, but loading and saving was slower than mollasses in January. I now use a medium lot and keep the decorations minimalist.
To delete memories:-
Select scrapbook from the main actions bar. Icon on left of your "Favorites", below your name.
Select the memory you wish to delete.
Click on it and an actions box will appear.
The dustbin is on the lefthand lower corner of the picture which shows on the left side of the action box.
Click on the dustbin and you will be asked to confirm that you want to delete the selected picture.