Then a little while ago, I wondered: could I do this with video too?
After some research, I realized the answer is "technically yes, but it's probably not a great idea." The biggest problem is how demanding it is to edit video if it's all being done client-side, especially via web frameworks like FFmpeg-wasm. From a hardware perspective, editing multiple images is extremely easy, but the same edits on multiple videos though... well, that can get really demanding. And what if it's being done on an old PC with bad specs? Or an old phone? Or a decade-old Chromebook? Would a batch video-editing tool that does everything client-side even make sense for that?
Well, I went and made it anyway. My reasoning is, being able to do client-side video editing from any device via the web is just too convenient. That's because I can't install proper video editing software on every device I use. I definitely can't even put regular ffmpeg on my computer at work because the I.T. Department would have a fit. But I can access a website and do most of what I need on there. I can access this from anywhere and since it's all done client side, I don't need to worry about slow WiFi or privacy or anything else. As long as the page loads, everything's good.
Anyway, I hope it comes in handy for other people. If you've ever needed to convert video or resize it or edit it, but don't have access to good software on whatever device you're on, then hopefully this will help out a lot.