From what you have described and from the pictures you provided, I believe you need to have the guitar properly set up. As part of a complete set up, you can have the actioned lowered as much as possible to make the guitar easier to play.
Lighter gauge strings might help but it appears from the pictures that the action has room to be lowered. Lowering the action can be accomplished in numerous ways. 1) The saddle (in the bridge) can be lowered by removing and carefully and evenly sanding the bottom of the saddle. 2) The nut can be lowered by carefully removing it and sanding the bottom (same as saddle). This is more difficult as the nut is not as easy to remove as the saddle. filing the nut slots deeper can lower the action as well but will diminish the quality of the tone. 3) Adjusting the truss rod to take some relief out of the neck. This is usually done after any needed adjustments are made to the saddle height and the nut height. But you might try adjusting the neck with the truss rod first as this is easily reversible, unlike sanding the nut or saddle which is more difficult to reverse.
I recommend that you engage the services of a luthier or qualified guitar repair technician to do the set up for you. Sanding the nut or saddle too much can make the guitar impossible to play without major fret buzz.
One other thing you might check since you purchased a used guitar, is the fret height. A guitar that is played often by a guitarist with a heavy fretting hand can exhibit excessive fret wear. If the frets are worn to the point where they are closer to the fretboard, the guitar will be more difficult to play. It appears that your first fret is fine but its hard to tell about the other.
It does appear from the picture that lowering the height of the nut might be helpful. But it's possible that lowering the nut height could necessitate raising the height of the saddle. This can be accomplished with a shim or a new saddle.
If you can't take the guitar to a professional for a proper set up at this time, you might consider looking closely at the neck to see if adjusting the truss rod might help. Ideally you want the neck to have just a slight relief in the center to prevent fret buzz. Check the amount of relief by pressing the low E string down so it is touching the first fret and the 14th fret (where the neck joins the body of an acoustic guitar). You have the optimal amount of relief if the string barely clears all the frets in between with the most clearance at around the 7th fret. If several frets are touching the string between the two you are holding it against, there is insufficient relief. If there is much clearance at all at the 7th fret, you may have too much relief.
If you think you have too much relief, try turning the truss rod adjustment screw clockwise (righty tighty) an eighth to a quarter turn at a time and check again. You can continue to make slight adjustments until you start to get some fret buzz and then turn it back in the other direction an eighth of a turn.
Here is an article about how and why to adjust your truss rod. Adjusting your truss rod
Another thing you can do to temporarily make your guitar more playable is to detune the guitar by half a step (half step flat) and put a capo on the first fret and leave it there. This will effectively make your first fret serve as a lowered nut and make the first position F barre chord (and all other barre chords) much easier to play.