While SkyPrep allows uploading files of any size, online document viewers have maximum size limits for what they can display. If you see an error notifying you that a file is too large, you can try changing the viewer or compressing the original file before reuploading it into SkyPrep.
Videos: No maximum
SCORM Packages: No maximum
PowerPoint Presentations: 200MB or less is recommended
Other Files: 20MB or less is recommended
If you find that your files are still too large, you can opt to allow learners to download the files instead.