Drizzle is like when you use a magnifying glass to make a tiny picture bigger. Imagine you have a little picture that's too small to see all the details. You put it under a magnifying glass and suddenly you can see everything much clearer!
In image processing, drizzle takes a small picture and makes it bigger by using information from nearby pixels to create new, more detailed pixels. Imagine each pixel is a tiny dot that makes up the picture. When you "drizzle," you add more dots in between the original dots to make the picture look like it has more details.
If you imagine a puzzle, the pieces are the pixels and when you "drizzle," you are adding more tiny pieces that will make the puzzle look bigger and more complete.
The word "drizzle" comes from the slow, gentle rain that falls from the sky. Just like how raindrops combine to make a bigger stream, drizzling combines small pixels to make a larger, more detailed image.