core/src/in/srain/cube/image/impl/DefaultImageLoadHandler.java
public void setLoadingBitmap(Bitmap loadingBitmap) {
        if (Version.hasHoneycomb()) {
            mLoadingDrawable = new BitmapDrawable(mContext.getResources(), loadingBitmap);
        }
    }
public void setLoadingBitmap(Bitmap loadingBitmap) {
        if (Version.hasHoneycomb()) {
            mLoadingDrawable = new BitmapDrawable(mContext.getResources(), loadingBitmap);
        }
    }
set the placeholder bitmap