Uploading a large PDF makes my page slow or crashes
Some PDF’s which contain a lot (thousands) of vector objects may slow down the VyewBook. If this is the case, export the PDF to a PNG file then re-upload it to your VyewBook.
Programs which may be able to export to PNG would be Adobe Acrobat, Adobe Illustrator or Adobe Photoshop.
If you do not have these programs, then try opening the PDF on your computer then using Vyew Desktop Screen Capture to capture it into the VyewBook instead of importing the file.