The resolution of an LED wall is indicated in pixel (number of image points). It depends on the pixel pitch and the size of the LED wall. With the number of LEDs per square meter, the resolution increases accordingly. The display of the shown images improves, but the price per square meter of the LED wall increases as well.
Like this, an LED wall with a surface of e.g. 5x3m, with a pixel pitch of 2.6mm, has a resolution of 1920(w)x1152(h) pixels. Hence the resolution depends on the wall and its own pixel pitch.