Help:Introduction to images with VisualEditor/4
Adding images to Wikipedia
Worth a thousand words
Editing the details
What am I looking at?
For large picture sets
Review of what you've learned
When you insert a new image, or double-click on an existing image in an article, a dialog box will open, where you can add details about the image and change its settings.
A good caption explains the image so that readers understand what they're looking at. Captions can contain wikilinks and formatting, just like the main text of a page.
Alternative text is used to describe the contents of an image for users who have visual impairments, and use a text reader for web pages.
The "Advanced settings" window contains various additional parameters. These include the alignment, the display type, and size of the image. It is usually best to leave the defaults as is, but sometimes a larger image may be more useful.