I have a lengthy list of free tools at The Best Tools For Creating Visually Attractive Quotations For Online Sharing.
Here’s a new addition to that list: Live Luv Create
You can use many of their stock images or use your own, and then add text. The two negatives to the site are, one, even though it’s free, you do have to register with it. Most of the other tools on my list let you create quotes without requiring registration. The other problem is that though it provides an embed code when you first create your image, unless you grab it then there doesn’t appear to be any way to find it again.
Here’s a sample of what a quick creation (thirty seconds) looks like