Please, change var iconUrl to "http://openweathermap.org/img/wn/%s"

[dnegorov]

https://github.com/briandowns/openweathermap/blob/73cba80d1d677713b4a1089cb7fea0780008cb1a/openweathermap.go#L33

On the page https://openweathermap.org/weather-conditions recomended to use URL like http://openweathermap.org/img/wn/[email protected] With this URL you can get image with different sizes by adding postfix "@Nx" to file name, where N can be 2 or 4: "50d.png" - defaul size 50x50px, "[email protected]" - x2 size 100x100px, "[email protected]" - x4 size 200x200px.

Example: owm.RetrieveIcon(".", w.Weather[0].Icon+"@4x.png")

And change var iconUrl to var IconUrl to make it changeable. In this case users can change URL to different icon set.