Why do screenshots taken from the same phone have different file sizes?

Question

Why do screenshots taken from the same phone have different file sizes?

In: Technology

Answer 1

Because a Screenshot will be stored as a PNG which is a lossless compression algorithm, or as a JPG which is a [lossy compression algorithm.](https://www.researchgate.net/figure/Examples-of-JPEG-artifacts-at-a-high-compression-ratio-At-a-high-compression-ratio-in_fig1_336010574)

What they are doing is that they don’t store each individual pixel, but rather shorter instructions that can be used to recreate the image. PNG for example can store something like “the area from pixel 0x0 to 100×100 is white” (very simplified) which even written as a sentence uses much less storage than writing down the value for each individual pixel.

So depending on how much similarity there is in your picture (lots of the same background color, text, etc) the file size can be decreased a lot

Answer 2

The phone will be using compression to make the image smaller. For reference, a completely uncompressed 8 megapixel (3456×2304 resolution) image would take up nearly 23Mb of storage, which is way more than most people would be happy using! So, the reason the actual file size varies is because the compression doesn’t always work as well–some images will be easier to compress than others, usually depending on how much detail is in them.

Answer 3

Images are compressed. Compression works by removing redundancies in the file, so the compression level depends on the contents of the image – some can be compressed more than others. For example, a completely blank image can be very easily compressed, while a random noise image can barely be compressed.

Answer 4

Photographs are rarely stored as raw data. A 1920×1080 image would be about 6 megabytes stored raw, but file compression algorithms let us get it smaller than that. These algorithms find patterns and shortcuts to use less data to store the same image. Depending upon the patterns that are used and how common they are in the image, it may wind up being significantly larger or smaller.

Answer 5

here are two shopping lists:

apple, orange, apple, pear, pear

and

apple, orange, orange, orange, orange

both our shopping lists have the same number of items, 5 (like our screenshots all have the same screen size)

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its nice to shorten things though, as then we can store more shopping lists in our notebook (or more pictures on our phone)

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We can re-write them as:

2 apples, 1 orange, 2 pear

and

1 apple, 4 oranges

now our second shopping list is shorter than the first, we have **compressed** the data.