Find all files (-type f) in the current directory (~) and its subdirectories, whose name ends with either .png or .gif ( -iname "*.png" -or -iname "*.gif" ) and move them to the Pictures directory in the home directory (~/Pictures/).
find ~ -type f -and \( -iname "*.png" -or -iname "*.gif" \) | xargs -I{} mv {} ~/Pictures/