rustyfemboy

Republicans: We're not Nazis, the Nazis were actually left-wing.

Also Republicans:

I wasted far too much time on that, holy shit.

Small miscalculation, 1 TB is only 10¹² bytes, not 10¹⁵ bytes, so you would only have 3840 * 10¹² bytes ⇒ 1280 * 10¹² pixels, so the width of a square RGB image with 3 bytes per pixel would only be around 35,777,088 pixels.

The average woman's height is 1.588 m and the average woman's shoulder width is 0.367 m.

Assuming that this average woman fits exactly in this photo, the photo's "area" would be 1.588 m × 0.367 m = 0.583 m².

Assuming the pixel format is RGB and 8 bits per colour channel, each pixel in the photo would consist of 3 bytes. 2 PB is equal to 2 × 10¹⁵ B, which divided by 3 B for each pixel means there could be at least 6.67 × 10¹⁴ in this photo. In reality most of the time images are compressed so in practice you could get even more pixels. How much more depends exactly on the image and the desired image quality.

To calculate the area of each pixel, divide the photo's area by the number of pixels. This gives 0.583 m² / 6.67 × 10¹⁴ = 8.74 × 10⁻¹⁶ m² for each pixel. To get the side length of each pixel, take its square root to get 2.96 × 10⁻⁸ m = 29.6 nanometres!

Dividing the widths and heights in metres by the length of each pixel gives (width, height) = (1.588, 0.367) m / 2.96 × 10⁻⁸ m = an image resolution of 12,412,583×53,708,941 pixels!

When it comes for feature size, the bottleneck isn't actually the pixel size. Assuming the image is in visible light, the shortest wavelength visible to the human eye is 380 nm, so increasing the resolution beyond that point is useless.

In such a photo where features as small as 380 nm can be identified. To quantify the resolution you can see these features in, define an "effective pixel" to be a pixel of side length 380 nm. The actual pixels in such an image aren't relevant at this point.

Individual skin cells can be identified being 30 μm / 380 nm = 79 effective pixels wide. With similar calculations, blood cells can be identified with a width of 18 effective pixels, and you might be able to even identify individual bacteria. An E. coli bacterium has a length of 2 μm, which is 5 effective pixels.