While there are several websites that make photographs and drawings available for free, there are several good reasons to use your own too.
First, you own the copyright, so unless you think you might sue yourself for copyright infringement, you have nothing to worry about on that score.
Second, being able to submit illustrations to accompany an article you’re pitching to an editor may make the article more attractive to the editor.
Third, for travel articles, you definitely want to be able to submit your own (high quality) photographs.
Fourth, for some kinds of articles, especially travel ones, you should be able to negotiate a separate fee for the use of your photographs.
Fifth, if you illustrate your blog or newsletter with your own drawings, readers may come to like your drawing style. I know that I enjoy reading certain logs and newsletters because of the of the writer’s quirky little drawings. I’ve also been told by some people that they like my drawings!
Sixth, given that you own the copyright, and assuming that you don’t give that away or sell it, you will be able to use and re-use your photos and drawings in the future in media that you may not have yet considered (such as books), or for non-written products to sell, such as calendars, and in media that has not yet been invented.
Finally, there’s a great sense of satisfaction in standing back and looking at an article that is, literally, all your own work.