Identical in every way ...

The EHT Collaboration created a flurry of images of Sagittarius A*, using ray tracing, a technique that visualizes the properties of the black hole based on data collected with the radio telescope array and predictions made by Einstein's theory of general relativity. The images shown here were created by UArizona's Chi-kwan Chan. Ben Prather/EHT Theory Working Group/Chi-Kwan Chan

Einstein's right yet again. Black holes scale in universal fashion thanks to Sagittarius A* black hole proving to be identical to M87*s monster.

Figure 4. Top: three example models of some of the best-fitting snapshots from the image library of GRMHD simulations for April 11 corresponding to different spin parameters and accretion flows. Bottom: the same theoretical models, processed through a VLBI simulation pipeline with the same schedule, telescope characteristics, and weather parameters as in the April 11 run and imaged in the same way as Figure 3. Note that although the fit to the observations is equally good in the three cases,they refer to radically different physical scenarios; this highlights that a single good fit does not imply that a model is preferred over others (see Paper)

One of the leading scientists behind the new breakthrough, Dimitrios Psaltis, professor of astronomy and physics at the University of Arizona, has revealed how the new image proved one of Einstein's predictions from his theory of gravity.

It's all down to the striking similarity between Sgr A* and MH7*, despite their massive difference in size — Sgr A*, which has a mass 4 million times greater than that of our Sun, is more than one thousand times smaller than M87*.

The new image of Sgr A* has proved one of the most fundamental predictions of Einstein's theory of gravity, Psaltis explained in a statement from the University of Arizona. Namely, the new data proves that the image of a black hole scales only with its mass. So, in other words, a black hole 1,000 times smaller in mass will look very similar; the only really discernible difference will be the size. 

Scale invarience rules.