The window also contains two text boxes in the Dimensions section that allow you to set your ... Tumblr adds the image to the editing box. You don't have to use HTML to resize a picture in your ...

(It can also require some monkeying around with HTML, which many ... uncheck the Resample Image box and change just the (confusingly named) Resolution field, which is set by default to ppi as ...

HTML doesn't offer as clean a solution for vertical lines as it does for horizontal lines -- a vertical equivalent to the Set your image up within your text and add a "style" attribute tag.