Hi both,
... but also pictures I don't want to lose. So what would be the best solution?
You will never find an app that knows which photos you think are important. Only you can do that.
The simplest thing you could do is import them all into the Apple "Photos" app. Then you look at each and give a start rating of 1 to 5 stars.
One tip, WRITE DOWN you rating criteria. I use something like this
zero- I've not yet looked
1 - very poor for technical reasons or just a worthless subject
2 - questionable quality or unimportant subject
3 - photo that might not be perfect but the subject is important to you
4 - a high-quality photo that is important to you
5 - publication quality, something you should be showing off
Then you can make albums that automatically populate themselves with rules like 5-star phots from summer 2011 trip to Spain.
There is not many other options, you are going to have to look at each photo and rate it and maybe add keyword tags.