How to allow website visitors to design PP presentations?

I am creating a website for teachers who often need to create PowerPoint presentations on vocabulary. Many teachers spend hours finding images and sizing and inserting them into presentations for their classes. I’d like to provide PowerPoint slides for these common vocabulary terms which could be arranged and used however the teachers choose. I’m thinking that there would be a searchable list of terms, maybe with four or five options for slides for each term, and the teachers would be able to click on the slides they want and then arrange them into a PowerPoint presentation of their own, adding only the title and end pages (and inserting any other pages of their creation if they choose). Teachers should be able to say what order they’d like the slides to appear in and to rearrange them, too. I’d also LOVE it if these same slides could be saved to be used as online flashcards for students who could login to personal accounts, download the teacher’s PowerPoints and review thier flashcards onsite.

I know that PowerPoint presentations can be posted and downloaded from websites in the same way that Word or .pdf files are often used. Do you think that this is possible? Would it violate any laws or copyrights or anything? Do you know of a good way to write a website that could do this? And can you recommend a web design service or program or something that would allow a great teacher but so-so web designer to accomplish this?

Any hints or tips are GREATLY appreciated!!!