Having only 5 images displayed is not always enough, especially with the products I provide because manufacturers provide a whole variety of images showing views of a product from the front, sides, back and angles plus close ups, images of the deluxe packaging/box, additional extras like accessories, light features and more.
Having the ability to add up to say a maximum of 12 or 20 would greatly help.
Images could be shown as usual below the main image or even have a scroller below the main image so you can scroll through a selection.
Also, when clicking the main image so you have the pop up window showing the image in the center of the screen, make these images larger.
(Image attached as example)