Thank you for your questions. For changing multiple products at once, there is no easy built in way, I did find a module in Prestashop's official site titled Mass Management products & categories premium.
For your 2nd question, we are happy to help, but will need more information to help troubleshoot the problem.
Are you getting any errors related to the missing images? They can help narrow down the cause. You can check the PrestaShop error logs in the Dashboard.
If you have any further questions, feel free to post them below.
well I looked at that module demo and i see option to move category to another category but I dont see how that is done but im sure it can be. Im broke and $100 in alot right now lol. I can just do it manuelly for now know I guess
well Im not getting any errors. I can see the images when i open up the item and view under image section but when viewing all the products all at once under products section i cant see the image icons so i dont know if thier are images. See alot of products dont have pictures so i want to delete a bunch at once versus opening each one and going to image section to see if there are any images associated with the product then if not I have to go back and check the box and delete just that product.
And I have been told by a friend he thinks the fact I have so many images not showing is why my site is running so slow that is why im trying to delete them, But i want to ask a professional opinion I why site is running so slow? Its really really slow and im not sure how to fix it?