This page describes specific settings for the Image widget. Note that generic widget settings are described on the Widget Generic Settings page, so if you cannot find the setting you are looking for check there too.
Be aware that you can simply drag an image onto the report page to automatically add an Image widget displaying the desired image. This will add the image to the ArcGIS Online organisation that you are signed into.
Image & Links
Type or use the browse button to generate the URL for the image you want to display.
Image alternate text
Type some alternate text to show if the image cannot be displayed e.g. for assistive technologies.
Type or use the browse button to generate the URL when the image is clicked.