No problem, nop will store your original full-size image with the thumbnails yes. The problem is that internally the binary image is loaded into memory from the database or disk the first time it is accessed. If you store original pictures in the database this will be returned EVERY TIME the picture record is accessed. In both cases this is a waste of resources as all the pictures are already in blob storage. Once the site has 'warmed up' and the page results cached you may see reasonable performance with pictures stored on disk. We have several thousand products which are constantly being added to. We also deploy updates quite often which clears the cache.
www.openforvintage.com
Conclusion : If you have a lot of products / high res images, you do not want to store them in the database and if you want to scale your site to large numbers of users you also don't want them on the webserver. Successful ecommerce sites need to serve pages in 3-4 seconds or less. You can get around this to an extent by throwing all your money at Azure but who wants to do that?