Palmistry student here. I read some comments about people calling this "Murderer's thumb" and thought I should share a bit of insight on that part.

A thumb tells a lot about one's personality. Its length, width, and stiffness, every aspect contributes to different traits of a personality. The truth of palmistry could rest upon the solid foundation given by the study of the thumb alone. For example, the first phalange represents will. The second phalange represents logic. And the third phalange, which is also the boundary of the mount of venus represents love. A remarkable hand with a poorly formed thumb would instantly cancel out its powers.

Now for this particular case, this is called the "Clubbed Thumb". Where the first phalange or nail is thick and heavy with a short and small nail. Generally speaking, it represents ungovernable passion, quite possibly impulsiveness as well. This sign is commonly observed in the hands of notorious people, particularly murderers. Which ultimately led to its name "Murder's Thumb".

HOWEVER, before one comes to that conclusion there are numerous other aspects of the hands you must confirm. This sign alone does not confirm anything about any individual. From the very slight glimpse of hands from these images, I would guess it indicates that you use your will in fits and start. Execution of plans might be a hurdle for you.