Known has several post types, each of which is good for particular content types. Sadly, one can't add photos to statuses or replies, though one could accomplish much the same thing with a photo post type.
In a "Post" type, one may need to switch from the plain text editor to the rich text editor to be able to insert a photo by clicking on the photo icon in the toolbar which only appears on the rich text editor. A modal window will then open up that will allow you to upload a photo and add metadata about it prior to inserting it into your post.
Tip: selecting the image in the post and re-clicking on the photo icon will allow you to edit the image source, description, and dimensions.