Navigate to “Settings” in the left menu from the WordPress Dashboard to access this area and click “Media” from the sub menu.
Image Sizes
When you upload an image to the WordPress Media Directory, WordPress will generate three additional, smaller images from the one you uploaded: thumbnail, medium, and large. If your original image file is smaller than one of these image sizes, it will not enlarge the image to create that size.
When you insert an image in a post or page, you will be able to select which of these image sizes you wish to use.
Additional image sizes may be added based on your installed and activated Theme or Plugins. If this is the case, you will see those size options when you go to insert an image in a Post or Page, but you may not be able to control those sizes and settings on this page.
- Thumbnail size – The thumbnail is the smallest rendering of your image. Thumbnails are commonly cropped to match the exact default 150×150 pixel dimensions. You can uncheck that default checkbox so that your thumbnail sized images will not be cropped and will render in the maximum width or height of the image (whichever is smaller)
- Medium size & Large size – Set the maximum width and maximum height. These images will not be cropped.
Uploading Files
- Organize my uploads into month- and year-based folders – Check this box to organize your media uploads. Your media file URLs will end up looking like this: https://www.example.com/wp-content/uploads/2020/01/nameoffile.jpg
This is recommended to prevent slowdowns that can occur when a file directory contains a very large number of files.
Further Reading: https://wordpress.org/support/article/settings-media-screen/