I made a wmm project using my drawings+audio tracks and am trying to save it but all the images become pixelated no matter which video form I tried (high res, cd, computer...). They're all in very high resolution and look good when I watch the result on my project, so I don't understand why it would pixelate when I save it.

To give you an idea the images are all about 5118x4094 pixel, 72 pixel per inch. I've tried making some of them 1600x900 pixel but they still appeared pixelated when I saved the file as mp4 or other format.

I've tried uploading it directly to youtube but it he same thing happened.