The maximum theoretical resolution R of a radio telescope interferometer,

from https://lcogt.net/spacebook/radio-telescopes/

is

R = 2.5 x 10^5 x W/D,

where R is in arcseconds and W (wavelength) and D (baseline) are in meters

W = 1.3mm = 1.3 x 10^-3 M
D = 1.2742 x 10^7 M (diameter of the earth)

R = (2.5 x 1.3/1.2742) x 10^-5
R = 2.551 x 10^-5 arcsec

1 AU = 1.496 x 10^8 km
Black hole diameter = 4.4 x 10^7 km = 2.941 x 10^-1 AU
Black Hole distance = 26000 ly = 7.975 x10^3 parsecs

The apparent angular size of an object is (size in AU)/(distance in pc).
Apparent angular size on the celestial sphere of the black hole is

(2.941 x 10^-1) / (7.975 x 10^3) = 0.3688 x 10^-4
Angular size = 3.688 x 10^-5 arcsec

So in the image formed by the interferometer, the black hole will be on the order of one pixel.