Images turn into black boxes
If you see black boxes on the live site where images should be, it is likely that the image file is corrupt in some way.
Typically this is a result of manually changing an image's file extension to something other than what file type the image actually is. For instance, in the case above, the image is a PNG file, but the file name was manually changed to "image-name.jpg".
Before uploading an image to the CMS, a good practice is to check if a file can open in your local machine. If it cannot open in any certain application, it is likely the CMS will not be able to process the image.