For Products you need to create a new Library for add the product images. 

1. Go to Content >  Images 

2. Create new library 

3. Go to menu and select the library. 

4. In the bulk actions select the Library properties 

5. Expand “Advanced Options”  

6. Click on the thumbnails sections and selects the thumbnails sizes. Please note that if the thumbnail sizes configured in the General Behavior section within SmarterCommerce Web Site Settings are not selected here in the library, then the original image size will be shown. 

7. Save Changes. 

Now you can upload the products images.