Look at both images in full size and compare their faces, the red/yellow transitions in the first panel, and anywhere there are details. The child post will have blocky chunks and distortions in color that the parent won't. Those are JPEG artifacts, "errors" made in the image due to the :math: used by the JPEG system to make the filesize smaller which Twitter adds in abundance.
How many mochi you wanna eat~?Happy New Year, and all the best this year too.
And stop with that "Mama", really...I mean, 2 of them...20 of them♪2 of them~♪By the way, you all~!Yes, yes...Happy New Year~♡Mama♡