Need help turning individual frames into a video

[Losonti Tokash]

For reasons I don't care to explain, I have a video that exists as many thousands of individual pictures and I'd like to animate them as frames. I tried using Windows Movie Maker but it made it over 12 hours long as it thought giving every frame several minutes before moving on was great. I can adjust them individually, but that's not practical since as I mentioned there are thousands of these things.

Does anyone know of a free program that I can more or less just throw these pictures into and get a coherent video out of it?