What does the underscore symbol before an import mean in Go?

Hello! I started learning Go and came across a construct I don't understand. In someone else's code, I saw this import: ```go import ( "fmt" _ "image/png" "os" ) ``` I'm confused by the underscore (`_`) before the `"image/png"` string. I know that in Go, unused imports cause a compilation error, but this is clearly something different. I tried removing this import, and the code stopped working — the program couldn't decode PNG images. However, I'm not calling any functions from the `image/png` package directly. How does this work? Why is such an import needed if we don't explicitly use functions from the package? In the documentation, I found a mention of `init()` functions, but I didn't fully understand how this relates. Please explain what the underscore before an import is used for, and in