The picture shows your left hand pinky out straight and flat on the table. I seems likely that you are working very hard to do that and the back of your hand is likely very tense.
If you lay your hand on your thigh, relaxed and palm up,there should be a natural curve in all of your fingers. From this position, relaxed and slow, move finger 3 closer to your palm, allowing the pinky to move with it if it wants to. Stop as soon as 2 starts to move. Make sure that you are not doing any work to straighten 2 out; keep it relaxed with a slight natural curve.
What you are attempting is to isolate the muscles needed to move 3 without engaging the muscles in 2 or 1. You can also practice this exercise moving 1 & 2 while keeping 3&4 relaxed. I find this more challenging in the beginning which is why I started with 3&4 being active. Muscle isolation is easier to learn if you are attempting it from a relaxed state. Once you get the outer and inner pairs isolated, then you can work on the individuals.
Practice this any time you are away from your guitar. I used to do it in meetings or when waiting for appointments.
Remember to keep your hand as relaxed as you can. The movements might be quite small in the beginning, but will increase with practice.
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Classical Guitar forever!