1. Click on the page's URL to view the page in your browser.
2. View the page's source code.
3. Find all appearances of "<img" by using the search tool. You can usually bring this up by pressing Ctrl+F.
4. Make sure that you have filled the alt tags on all images. If you have not, then the quotation marks after "alt=" will have no text between them, as pictured above.
5. Once tags have been added to all images, update the page using the MySite tool.
If the issue persists, please contact support.