system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How is it decided how much memory a picture takes. Like what makes a difference and why do some pictures take more memory than others.
gpt
This depends on the type of compression used and with many compression algorithms depends on the complexity of the photo. 

If the photo is comprised of simple shapes and solid colors then it compresses better than a complex scene with many colors.