You may want to simply add them to the QAT, storing the modifications in the template holding the macros. (It depends on the number of macros.)

It is then relatively easy to use the Notepad or XML Notepad to modify the images and tooltips. in the CustomUI.XML files that you would extract from the template containing your QAT.

Modifying the QAT in Microsoft Word
Modify Quick Access Toolbar (QAT) Button Image or Text

This is a lot easier than creating a custom ribbon from scratch or modifying the export file.

[Edit] I see you are using your own images, that would require a Ribbon customization. OTOH, the number of mso images available is large (much larger than the number available directly through the interface). If you use one of the mso images, you do not need the ribbon customization.