Once you familiarize yourself with the various stock photography sites that offer free photos for your blog, you might decide to add a celebrity picture to your blog. The ideas you come up with for your own blog photos are as endless as your imagination.
But, keep in mind that lots of photos are taken of celebrities and not all of them are legal to use. Even if you find a celebrity photo you like on a stock photography site, be certain that the photo is not encumbered with potential copyright violations, royalties or other legal technicalities.
By choosing stock photography sites that are reputable, you will be more assured that all the free blog photos you use are legal. But, keep in mind that often a model release must be obtained when taking photos of celebrities and even people who are not celebrities.
In the age of camera cell phones, you might think that any photo can be used at any time or for any use but that's simply not true so investigate usage rights before you download.