What is a good file size for a 300 by 300 pixel photograph sized for the web in JPG format?

I literally just tested both reducing an image from 1000x1500 to 300x300 to test and saved for web in jpeg form and it came out as 4k i did the same with just creating a blank document and saving it for web in jpeg and it was also 4k. It may depend on the dpi but that was not specified in this question so 50k is wrong.

50 k