4K HD Wallpaper: Fire Sparks
The 2nd photo from Adrian Pelletier's portfolio. This one I think is a long exposure image. Check it at full size to see if you like and download under CC0 license for use in desktop backgrounds, homescreen phones, blogs, content marketing, social media, webdesign projects...
Widescreen Desktop / Macbook (Retina): 2880x1800 (fits on: 2560x1600, 1920x1200, 1440x900)
High Definition HD 1080p: 1920x1080 (fits on: 1600x900, 1366x768, 1280x720)
Samsung Galaxy Tab & iPad: 2048x2048 (compatible with many tablets)
HTC, Samsung Galaxy & iPhone: 1080x1920 (compatible with many phones)