How do you create such icon background

Now I have seen such icon backgrounds so many times. Any idea how do they add this background, any online tool/Photoshop brush for that?

https://play.google.com/store/apps/details?id=drv.games.timon

It’s called burst of rays effect, google it.

Most likely done in some vector program - Inkscape or Adobe Illustrator.

Yes, this is definitely a vector , check this out…

I use Paint.net for this (free). This is done using layers. The icon has 4 layers. the rays, the gifts, the bear and the border. Just takes a few minutes to make. No vectors needed for the icon.

Can Gimp not do this?