Non squared door frames

[North]

I was trying to fit three new doors in my bedrooms when I realized that the door frame is not squared. There is at least 1cm difference between the right and the left height in the three doors and the bottom and top width is slightly out as well.
The old doors where flat and cut to shape and size but my new doors are panelled so If I do the same it will be noticeable.
What is the least destructive solution?

 

[Norcon]

I'd slice a 50mm slip on the band saw for the head.
12mm down to 2mm. Glued and nailed on.
Then pack out the door stop.

For the sides release the screws and pack out until parallel.

 

[foxhole]

I had same problem with a frame , cut out 10mm from high side and let it drop packing above.
Not sure why Norcon suggested packing door stops as they should be thick enough to cope with any misalignment in frame as is.

 

[North]

Thanks for the replies. Can you clarify what do you mean by pack out the door stop?

 

[Norcon]

The door stop will lap the correcting slip by about 10mm.
So the outer side needs packers.
If you can saw it the full width of the frame then great, but more difficult.
A hand plane would do the job also.

The architrave then covers up the modification.

Sawing 10mm out of the frame might be a better method if you can figure out how to do it.