The default warning value is set to 256K. This means that an image with a size not exceeding the specified amount will be copied completely, without binding. For images having a larger size, you can either use a binding, or import all the information. I recommend to connect all the image files, regardless of their size. If you do not use this approach, it is likely origin in the service project office with no additional graphics files. Theoretically, if all the information is imported into a document, there is no need in the binding.
But the reality is that, sooner or later, some of the files are subject to change. To link to the main document all of your images, do the following. When none of the documents is not open, click Link Options (Communication Mode) in the Element menu.In the list of Graphics (Images) uncheck Store Copy in Publicaton (Keep a copy of the publication).Ignore the warning dialog box settings.