Consider the diffraction pattern for a small pinhole. As the size of the hole is increased

We know that width of central maxima is given by

where λ is the wavelength of light used and D is the diameter of hole or circular slit

When the size of the hole is increased, the width of central maxima decreases and as the size of slit decrease more and more light will pass through it, hence intensity will increase.

Intensity is also increasing due to the concentration of light on a smaller area.

We know that as the size of the hole will be increased it will go closer to the wavelength of light and hence diffraction phenomena will start to decrease which will ultimately give us a sharp bright light at the centre whose width will be less as compared to the original width.