In general, the picture size of Little Red Book should be 3:4 or 1: 1 as far as possible, so that it is not easy to automatically cut when uploading, resulting in the contents in the picture being invisible or incomplete in the thumbnail. After the picture is uploaded, it can't be modified.

3:4 is a vertical screen, so the content is presented better and will not be crowded. Of course, the content needs to be typeset by itself, otherwise it will be crowded. The size or horizontal size is too long, and the content is not easy to present. Once there is more content, it will appear very small.