1920×1080 minimum, 3840×2160 for 4K monitors. Check your exact resolution in display settings before downloading.
Standard 16:9 wallpapers will crop or stretch. Search specifically for ultrawide or 21:9 tagged wallpapers.
Look for phone-specific crops, not desktop images resized — composition often breaks when a landscape image is cropped to portrait.
Requires a dedicated app (Wallpaper Engine, mobile live wallpaper apps). Uses more battery and system resources than static images.
No — only if it matches or exceeds your actual screen resolution. A mismatched high-res wallpaper gets downscaled and provides no visible benefit over a correctly-sized one, while using more storage.
Animated wallpapers render continuously in the background rather than displaying a single static image, which keeps the GPU active even when you're not using the phone.