Navigate to Teams tab from Manage User & Roles from the dashboard to access your "Sales Team". Press the Edit button and go to Images tab to specify the image library permission to the sales team.
Set the Restriction mode to active to customize the image library content that can be set to your sales team.
The sales team can now manage image library from the Content Libraries dropdown and "Images" menu o the main dashboard screen.
A screen similar to the below will display, showing a thumbnail view of existing images. You can use the "Name" and "Folder" fields to easily find your images.
The "Add Image" button at the top of the screen will allow you to drag and drop multiple images for uploading. Just drop them on the upload area and they will automatically start to upload. Default values for the folder and names are automatically provided.
As expected any image can be edited (title/text changes or swap the image itself), deleted, you can also upload one image at a time using the button towards the bottom of the screen.