4K HD Wallpaper: Violinist singing a song
The 1st 4K picture from Niek's portfolio featured in gallery and available from his courtesy under CC0 license for use in various projects (blog articles, apps, templates...) or just to have it as desktop background or homescreen phone.
Widescreen Desktop / Macbook: 2560x1600 (fits on: 1920x1200, 1440x900, 1280x800)
High Definition HD 1080p: 1920x1080 (fits on: 1600x900, 1366x768, 1280x720)
Samsung Galaxy Tab & iPad: 2048x1536 (compatible with almost all tablets)
HTC, Samsung Galaxy & iPhone: 1080x1920 (compatible with many smartphones)