Why is in this loop memory leak?

[SMcNeill]

No, my computer is weak. All I get is the program crashes into a gray window with a spinning blue circle icon followed after a while by a system error message. After all, my operating memory is probably not enough for so many hardware images, that could explain everything. The desktop computer does not work, its processor has gone to silicon paradise and the laptop has not enought power.

That's probably what you're seeing.  You're using memory faster than you're freeing it, until it runs out and then crashes.  Slow things down in there somewhere and see if the problem doesn't clear up for you.

[Petr]

Steve, I'm going to try it on better computer, mine stays in a gray screen with a blue circle icon and that's it. But it is true that the size of the used memory is stable around 2.2 GB

[Petr]

Result on the "better" laptop is message "list_add: failed to allocate new buffer, structure size: 116"

[Petr]

Thank you for the explanation. My intended way of using hardware images is so hardware intensive that I have to reconsider and implement my idea differently. Thank you for your patience.