If you'd like to output to an arbitrary writer, you can use the Image method.

https://godoc.org/github.com/mmcloughlin/globe#Globe.Image

This can be passed to an image encoder like

https://golang.org/pkg/image/png/#Encode https://golang.org/pkg/image/gif/#Encode https://golang.org/pkg/image/jpeg/#Encode

These functions take io.Writer objects. SavePNG was provided for convenience.