# LineIntegralConvolutionPlot image syntax?

Mathematica 12.2 help documentation states: LineIntegralConvolutionPlot[{{vx,vy},image},{x,xmin,xmax},{y,ymin,ymax}] generates a line integral convolution plot of image convolved with the vector field {vx,vy} as a function of x and y.

One of the examples shown includes the code snippet: LineIntegralConvolutionPlot[{{-1 - x^2 + y, 1 + x - y^2}, {Automatic, 320, 64}}, {x, -3, 3}, {y, -3, 3}]

I don't really understand how {Automatic, 320, 64} specifies an image-like argument. From the context of this and similar examples, I can guess that "Automatic" specifies a white noise image and that "320" and "64" refer to the pixel width and levels of color quantization of that image.

But does someone know where can I find actual, detailed documentation of this particular syntax? Thanks!