Adding new product images + assigning them to colour variants
Continue adding your photos directly within the product's admin page. Place the photo you want to have as the 'featured' image in the first spot.
You can still delete an image on the product page, but everything else will now be done in the Variant Image Wizard
When you add a new image you MUST subsequently add it to the app. If you don't, it will not display at all on the site.
Rearranging the order of the images is also done in the app (except the featured image that appears on the collection page, it will stay put)
Add the images as usual then navigate to More Actions, and select Edit Variant Images
Once in there you can bulk add/edit by selecting all variants of the same colour and clicking the bulk edit icon in the top right
Assign the desired images to that colour, then rearrange them if desired. The app autosaves your work