How to stop text "flowing" up past the bottom of a photo?

It’s been a long time since I built a website and I’m very, very rusty. Hopefully someone can help with this simple problem.

I’m creating a page of photos and text for a “work in progress” website. The photos will float left or right, and beside each photo will be text. I want the text to wrap below the photo when needed, which is what I already have and it works just fine

Here's the problem: "IMAGE TEST one" works, but having a smaller amount of text, as with "IMAGE TEST two," the text from the paragraph beneath it flows upward. How do I prevent that from happening?

Many thanks!