There is no length limit for photo blogs so you can insert as much text as you like.

The typical use of a photo blog is to tell a story with photos and captions in a narrative, journal-like fashion. Captions are usually one or two sentences long. But, of course, it's great to sometimes have entire paragraphs to set up the story or journal, or to expand on a particular element.

Here is an example of a photo blog:

Notice how the photos and captions are centered and how you can use fonts, bold face, etc. within your captions.

Also, the first two photos are formatted side-by-side by creating a small table of two cells and placing the photos and captions within the table cells.