Although it’s possible to resize your images once they’ve been uploaded into WordPress or LibGuides, it’s usually best to resize them prior to uploading. Resizing within the WordPress editor (or any editor) doesn’t actually resize the picture – it just tells the browser to display it smaller. We recommend nothing larger than 1000px wide or more than twice as big as you wish the final image to display. If you need help with this, please contact lib-it-help@list.uiowa.edu.
Always keep in mind those who cannot see the page well. Images, when possible, should be used to supplement textual information, not replace it. It often helps to develop your content without images and then add the images.