Switching your view to Details is also very useful for reviewing many images at once to look for large images.
Images - Finding large images in your account
Visit the Images section and click on Properties. You'll be able to see all the images in your account sorted by File Size. You can use this information to find larger images from your account to help you optimise space.
If you are running low on space consider optimising your images or upgrading to a plan with more storage.