==> All desktop wallpapers versions are available in 2 levels of quality :
- "Full HD" = JPG format (compressed at 80%) : best choice for screen resolution up to 1920x1080 which provides an optimal quality, a lightweight size and a fast download
- "4K UHD" = PNG format (uncompressed ) : best choice for screen resolution up to 3840x2160 which provides a high quality, a huge size and a slow download