Atom Does Not Let Me Add a Picture

On Atom, I added a hyperlink that led to another page. However, whenever I type on that new page, the text seems to be grey. It does not let mr code or add a picture. For example, when I write: <img src="Picture address" alt="picture name", <img src="Picture address" alt="picture name" will be written on the page and the picture won't be seen. I checked my code over and over again but I still can't manage to find out what's wrong with it. Thank you in advance!