At the point where you want to number images, start a new paragraph. Then click on the numbers in the paragraph section. Import your first image while the cursor is on the same line as the number. Make sure the image is set to a position of "in line with text. It is then part of that line. To automatically number image 2, go to the end of the first line (after the image) and press enter. Then next line (paragraph) will be numbered 2. Again make sure the cursor is on the same line as the two, import the image, and make sure it is set to a position of "in line with text", this is usually the default. follow these steps for each image and they will all be automatically numbered.
Reference 》Insert caption
This puts a caption such as Figure1... under the figure, wroth your descriptive text as the figure title: "Figure 1 My house". Each figure caption is auto-numbered, and updates as you add/delete/etc.