On the flip side, photo bombers are going to lose their you-know-what at the new level of visual fidelity. At least it pertains to the number of pixels, anyway. Granted, there is more to camera performance than the raw pixel count, but a 64MP sensor sure does have the potential to be something extraordinary, considering it's on a smartphone.
While it's a low resolution photo, the zoomed-in section highlights what kind of details a 64MP camera can pick up. Notice not just the individual strands of hair on the feline, but the characteristics of the eyeball, most notably the reflection. Then look at the photo as a whole to put it into perspective—the zoomed-in section is a small part of a much bigger photograph, with a remarkable amount of detail.
Outside of the pixel count, there is no other pertinent information included with the post. So, it is anyone's guess as to the actual camera sensor being used.
That said, XDA Developers brings up a good point, which is that Samsung's ISOCELL Bright GW1 is currently the only known 64MP smartphone camera sensor. However, Qualcomm did say earlier this year that we might see 64MP and 100MP+ camera sensors before the end of 2019.
We'll have to wait and see. Same goes for the precise smartphone model that this ends up find its way into.