Text that describes a picture is commonly referred to as a "caption." Captions provide context, details, or commentary about an image, helping viewers understand its significance or content. In various media, captions can enhance the viewer's experience by adding information that may not be immediately apparent from the image alone.
You are describing what is called illuminated text. See the link below for some history and examples of this art form.
text would be a link if a picture it is called an image source object /ISO
A diagram is a picture that goes with text and usually gives an example of what is in the text in picture form.
Colophon
The term is self describing; it is a feature that formats text.
To enhance the visibility of text on a picture, you can try increasing the contrast between the text and the background, using a bold or larger font size, adding a drop shadow or outline to the text, and ensuring that the text is placed in a clear and uncluttered area of the picture.
It's called a concrete or visual poem. Picture Poem see Bedford Introduction to Literature 8th edition
A picture that helps tell a story or explain an idea is called an illustration. Illustrations are visual representations that accompany text to provide clarity or enhance understanding.
The antonym for "text" is "image" or "picture."
you can only get a text slideshow if it is a picture message
Picture/phototitle
When a picture is positioned directly within the text at the insertion point, it is referred to as an "inline image." This means the image flows with the text, adjusting its placement as text is added or removed. Inline images are commonly used to enhance the visual appeal of the content without disrupting the text's flow.