Below are some examples of images which have been added as global widgets
On the left the images have a ratio of 3:4 and on the right they are 4:3. This is not enforced in the global widgets but it is used as a default for most images.
Image size: Images are being sized by putting a limit on their height. The width is left as auto and is determined by the aspect ratio of the image. If you prefer a different height for most images across the site, create a new global widget.