Better is to create one folder such as "Genealogy." In that folder create a "Multimedia" folder and include your gedpkg file. Here is sample folder/file structure:
Genealogy (a folder)
Multimedia (a folder)
MyGenealogy.gedpkg (a file)
Now put all your multimedia objects into the Multimedia folder or in any subfolder in that folder. GEDitCOM II will find them all (because it looks for multimedia files starting in the same folder as the gedpkg file. You can also designate the "Multimedia" folder as a known multimedia library folder for your file (but not required here). Whenever you want to copy files to another computer, just take the entire Genealogy folder.
The problem with putting them in the gedpkg package file is they could get lost after save or save as. The usual method to save a package file in Apple programming tools is to create a copy on the disk. Then when save is done, remove old one and replace with copy. This process is "fail-safe" approach in case of power failure during a long save. The old file is not overwritten until new one is completely on the disk.
The issue with putting other files in there is that they will not be copied to the new version and therefore would disappear when old version is removed. A while ago, some users wanted to use versioning tools, like SVN, to keep updates to their gedpkg files. Because SVN writes files into the package file, those files were getting lost after saves. I built a feature in GEDitCOM II to look for SVN files (and even out-dated CVS files) and copy them too during every save. You would not want to do the same for multimedia files because copying them over for every save could be very slow. The better approach is to create your own "package" file in the form of the above "Genealogy" folder.
See help window too on working with multimedia. It has more ideas for organizing your multimedia files. It is also interesting to extend multimedia to much more than pictures such as movies, sound files, documents, or basically any other computer document. You can configure "Helper" applications to handle any type of object you might want to add.
John Nairn