All images from Pixabay are released under the Creative Commons’ public domain deed CC0. Simply put, you can copy, modify, distribute, and use the images, even for commercial purposes, all without asking for permission or giving credits to the artist. However, do note that depicted content may still be protected by trademarks, publicity or privacy rights, especially if they contain recognizable people or logos.
To find out more about the usage of Pixabay images: https://pixabay.com/service/license/
Credits to PixelRockstar, “Pixabay joins the Unsplash Image Licensing Earthquake”: https://www.pixelrockstar.com/pixabay-joins-unsplash-image-licensing/