You can share any type of file. The application converts your file(s) into Upfiring files (.ufr extension) and encrypts them, so that all transactions that occur on the network are private. There are no file size restrictions.
We debated this, but the main reason we used Ethereum over Bitcoin were for the smart contracts. The application is completely decentralized so we needed a way to manage and distribute funds to seeders. As such, the main UFR smart contract manages the funds for all the seeders on the Upfiring network and is able to move them within the contract whenever a file is downloaded. It also solves the issue of having multiple seeders. With Bitcoin, you'd have to send a transaction to every seeder when downloading a file which would be detrimental for files with 20+ seeders. By using a smart contract, the downloader can make one transaction to the contract and the funds will be distributed to all seeders appropriately. The way we have it set now, the original seeder (content creator) gets 50% of the funds, while all other seeders on a file split the other 50%.