If you are having display issues with Image, this article will help you understand and diagnose your problem. This article only covers Image when accessing images via http or https. Image Pro, which uses embedded image data is not covered by this article.
Image fundamentally acts to build up an HTML img tag within your report. The link to your image file gets added as the src attribute within this tag. Here are some generic issues with your image data that may contribute to display issues.
However, the most common issue with displaying image data is due to permissions. When displaying an image in the Power BI online app, your image should be publicly accessible. Or, any authentication should be within the image url (for example, Azure Storage Blob SAS). Even if you can access the image when accessing the url from your desktop computer, it may not be accessible when viewing a report within the Power BI cloud app.
How can you test if the problem lies with Image? Try testing out the image url with the Power BI table (grid) control.
Add a table control to your report and drag in the column with the image url you are attempting to display. If the table control cannot display your image, then the problem is either the image, or more likely permissions, as described above.
If the table can display the image, then feel free to open a support case so that we can investigate further. However, we will need the url to the image in order to fully investigate your case, so please provide that so that we can assist you.