open up the text box option. it should be on the left hand side panel and it has an uppercase "A" on it. in my program it's the 5th one down.
You can also edit your photos in a photo editing program. You can go in and put watermarks on photos or websites or names..whatever you want. Just type it in. I have photoshop...so that's what I use. I am a huge digital camera buff and do photography now and then. But you can search for free photo editing software..maybe get some hits.
I'm with Tat, I normally use a photo program. just my preference, I can navigate easier. 
I don't mark my cake photos. Maybe I should. But, I do mark all my concert pictures...thousands of them...because they kept turning up on other people's websites with the implication that they had done the photography. So, I started using a watermark like the one at the bottom center of this photo. It looks like embossing and uses the colors in the photo itself. I think it's subtle enough not to detract much from the picture, but it's the devil to edit out. It's a three or four step process in Paint Shop Pro. I'm sure you could do approximately the same thing in PHotoshop. If you've got either of those, PM me and I'll be happy to give you the steps.
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crimsicle Concert photographer- other hidden talents!
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