# How to generate such an image?

Inspired by this, I'm using Graphics to generate such a image, but it return

I want every disk to be the same color. How to modify to make it work? Using image related functions is OK, DiskMatrix etc.

Graphics[Table[{{Opacity[0.5],White,Disk[{0,0},11.25]},
{RGBColor[{136,28,255}/255],Disk[{x,y},0.25]}},{x,-15,15},{y,-15,15}],


Take the large disk outside Table and use Opacity[1]:
Graphics[{Opacity[1], White, Disk[{0, 0}, 11.25],