FYI. I already posted this information.
The report shows HST images that support Einstein GR and gravitational lensing. I like to dig a bit deeper, here are two reports on WFI 2033-4723 (one of the HST views shown) showing its redshift number or z number and arcminute resolution in the spectra.
H0LiCOW - X. Spectroscopic/imaging survey and galaxy-group identification around the strong gravitational lens system WFI 2033-4723
Here is another report,
https://ui.adsabs.harvard.edu/abs/2019MNRAS.tmp.3214N/abstract
If people study and read the original reports (quite extensive and math intense modeling, all available at the links), it is the velocity dispersions measured that leads to the explanation of dark matter in the galaxies studied. "We use the Gemini and ESO-Very Large telescopes to measure the spectroscopic redshifts of the brightest galaxies towards the lens, and use the ESO-MUSE integral field spectrograph to measure the velocity-dispersion of the lens (σ _{los}= 250^{+15}_{-21} km s-1) and of several nearby galaxies."
The space.com report did indicate some of the metrics in their report "These Hubble Space Telescope images include reveals four distorted images of a background quasar and its host galaxy surrounding the central core of a foreground massive galaxy. Using the effects of gravity within this system, researchers were able to indirectly detect dark matter and find clumps of "cold dark matter" smaller than any similar clumps ever detected. "
FYI, all measurements for dark matter going back to 1933 with Zwicky - are indirect vs. seeing dark matter directly like carbon or iron in the spectra of the Sun or stars.