You can sometimes save some photos from your phone to Pinterest. Simply click on the share button on your gallery then choose to create a pin. This will allow you to save your own image as a pin in one of your boards. Another option that is available for you is to drag and drop your image on the board where you would like the pin to be created.
You can add a description on the URL if in case you would like to link the pin to your website or to your blog. Choose a board and save the pin on that board. By doing this, you can keep everything organized. Creating your own pin does not have to be complicated as long as you would do any of the available options.