system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is sending images on messaging platforms like discord considerably slower than video call, where you're sending each other over 30 images per second almost instantaneously?
gpt
**Sending an image** is a kind of file transfer. It uses a TCP (Transmission Control Protocol), which is connection oriented. Essentially, all hosts (i.e. both you and your friend's computer, or each computer and a server in discord's case) care about what is being transferred and if it was done so correctly.

It does this by sending both the image itself and a 'hash'. The hash is just the image data sent through a particular algorithm resulting in a string of what appears to be gibberish. However, the receiving computer can run the payload (the image you sent) through that same algorithm and compare the hashes. If they match, the image was sent completely without error. If not, the whole thing must be sent again.

**Video Streaming** typically uses some connection*less* protocol (like UDP). In this kind of interaction, both hosts don't care what is being sent or if anything is lost. If some packet doesn't make it or is damaged, it just moves on to the next like there isn't an issue. This is considerably faster but you will inevitably end up with packet loss (and stuttering/blurriness) unless the connection is perfect.