修改源码如下，这个问题主要原因是没有根据图片实际尺寸设置壁纸大小

public static Point getDefaultWallpaperSize(Resources res, WindowManager windowManager,Activity activity) {
        if (sDefaultWallpaperSize == null) {
            Point realSize = new Point();
            windowManager.getDefaultDisplay().getRealSize(realSize);
            int maxDim = Math.max(realSize.x, realSize.y);
            int minDim = Math.min(realSize.x, realSize.y);

            // We need to ensure that there is enough extra space in the wallpaper
            // for the intended parallax effects
            final int defaultWidth, defaultHeight;
            if (res.getConfiguration().smallestScreenWidthDp >= 720) {
                defaultWidth = (int) (maxDim * wallpaperTravelToScreenWidthRatio(maxDim, minDim));
                defaultHeight = maxDim;
            } else {
                defaultWidth = Math.max((int