Step 1: « Media »
To begin with, the 'media' tab works like a product library, a cloud in which you can store all your images.You can see in 'assets' the total number of images, you can also change the layout of the images, see the total number of folders on the left.If you want to add a folder, you click on the '+' tab then save.If you want to move an image to a folder, you select it here at the top right, do 'move', select the folder then do 'assign'.
Step 2: « Download an image »
If you want to upload your image, click on "Upload", then "Browse" (if you upload your image twice, it doesn't matter, there won't be any duplicates, it will simply overwrite the first version). Once they are imported, they are automatically cropped and assigned directly to a product that you will have entered in your file when importing it.
Step 3: « Delete and restore »
If you want to delete your image, click on the 'trash' tab, and if you don't want to delete it in the first place, don't panic, go to the 'deleted media' tab, select it and click on 'restore'. If you're importing several images, it's important to see if all the images have been imported, so look at the tab with the three little dots at the top right and click on 'missing media', and you'll be able to see all the images that haven't been imported.