You're going to have to narrow down your requirements.
E-Commerce covers a wide range, from folks running their own storefront, to folks using a service.
Your footer here indicates an iMac Pro. That'll work. Overkill for many cases probably, but it'll work.
An iPad and maybe a pencil can be used for graphics work.
And as for working with the images, there are discussions of the scale and scope of the store–a dozen items and a hundred items are a rather different discussion from a million items. A few images can be manual, a thousand becomes more difficult, and a million means automation.
And whether you're seeking to automate specific image processing, or to create tailored images for whatever this site is involving, or if you wish to create and sell your own artwork. Different and divergent directions await, here.
At the low end of acquiring and re-selling "stuff", a camera such as an iPhone can work well enough to photograph the images and to get going, and an iPhone can do some in-device editing.
Further up in cost and effort and capabilities, you're headed for image editing apps, and there are various choices here. Affinity Photo, Acorn, Procreate, Adobe Photoshop, etc.
And you'll need to decide if you're mostly working in one place, or if you need to be mobile while you're working.
And you'll want to consider what hardware or software or services will be needed for maintenance tasks, such as backups. And whether you need a second computer, particularly if your main computer becomes sufficiently critical that having it repaired can damage your business.
You'll want to consider how much memory and storage you need within whatever device or computer you pick, too. Images suitable for posting on a website are smaller, while video content can require much more storage.
How deep an archive of images and media do you need to keep, too?
Again, you're going to want to and need to narrow your plans, if you want more than very general suggestions.
