With the Images panel included in the Combinations grid, associating images to combinations is ever so simple, as shown on this video:
You first select the combination and then tick the box of the image you want to associate.
Of course you can select multiple combinations if you need to associate the same image, and also use the mass association icon on the toolbar of the Images panel to associate multiple images (once you have selected the corresponding lines).
Conversely, you can verify which images are associated to combinations, but clicking the image. Automatically, the associated combinations will be highlighted.
Also note that mass-associating images to combinations can be done using Store Commander's integrated CSV Import tool - see related articles below.