ENGDOCS-2238 (#21029)

* ENGDOCS-2238

* ENGDOCS-2238

Author: aevesdocker

content/manuals/compose/how-tos/file-watch.md

@@ -22,6 +22,8 @@ aliases:
 
 You don't need to switch on `watch` for all services in a Compose project. In some instances, only part of the project, for example the Javascript frontend, might be suitable for automatic updates.
 
+Compose Watch is designed to work with services built from local source code using the `build` attribute. It doesn't track changes for services that rely on pre-built images specified by the `image` attribute.
+
 ## Compose Watch versus bind mounts
 
 Compose supports sharing a host directory inside service containers. Watch mode does not replace this functionality but exists as a companion specifically suited to developing in containers.