What do you mean by "episerver commerce backend" - is it the catalog UI, or Commerce Manager? If it's Commerce Manager, then no.

"we are not using product images the standard way."  -> which way are you using it.

Are your images provided as assets in episerver or how do you link them with the correct product?

Are your images provided as assets in episerver or how do you link them with the correct product?

I mean in: /episerver/commerce/catalog, so Catalog UI.

The products in episerver have no knowleage about their images at all - they are just shown on the websitet by convention based on the product id. So no they are not provided as assets in episerver.

Then I would say no.

If it is important for you I would recommend that you try and implement a custom content provider for your images and apply that convention logic to link your images as assets to the products inside Episerver.

It's (officially called) Catalog UI.

So no, not with an easy way. The image showing in a product editing view of Catalog UI needs to inherit from CommerceImage, and then attached to the product via CommerceMediaCollection (aka, become an asset).

Of course you can accomplish it, but as far as I know you can't do it without hacking around a lot. (We're talking adding javascript to a property's desciption attribute on the page tag that crawls the id and inserts an image after fetching it by the ID....)

Edit: Above is absolutely not the way to do it, but if you were forced into a corner with a gun and you have 2 developers 1 hour it's one way to go ^^ 

Okay - it is not possible to make it with some kind of Assets provider?

My memory is rusty here, but if by default Commerce use the CMS Asset system. It should be able to write your own provider - IIRC some customers wrote their own implementation so they can support CND and such. 

Newer versions of Commerce uses the same asset system as CMS you can written your own content provider for images but as far as i know you still need to populate the products(CommerceMediaCollection as Quan said) with contentreferences to the right images in your new provider.