Normally when you insert graphics in Help+Manual you only insert references to external graphics files. This is also the recommended way for handling graphics because it is much more efficient and prevents your project file from getting too large.
There are two kinds of images that actually get embedded in your project files as encapsulated binary data: Embedded OLE objects and images pasted together with text from word processing programs like Microsoft Word.
For technical reasons embedded images use up many times their own size in memory and also place quite a heavy load on system resources. If you use a lot of them they will also significantly increase the size of your project files, which may slow down the functioning of the Help+Manual editor on older computers with limited memory.
See Embedded OLE objects and Inserting OLE objects for information on how to use OLE objects in your projects without embedding them. Embedded OLE objects are also embedded in your topic files, which bloats the files unnecessarily.
When you paste graphics together with text from MS Word you will be prompted to convert them to external files. You should always do this to avoid bloating your topics with embedded images. You can also convert embedded images later: by right-clicking on the graphic and selecting Convert Embedded Image in the popup menu.
When you click on an embedded image it does not appear as a "negative" image. Normally-inserted images appear as negatives with all their colors reversed when you click on them. You can also locate embedded images in your project with the Report Tool: Perform a full report with image references and then search for the word "embedded" in the report.