Polka Dots #6 (alternation needed?)

 

This is a long silk dress. I had never had the heart to cut it short. 

Today I put on a belt and pulled the dress over the belt to shorten the hem. 

Picture 1 is the longer dress look.

This is below the knee look

 

This is knee length look.

 

This is above the knee look.

 

Shall I do an alteration? What length suits me best?