Don’t you upload the patterns via “Account” and then “Upload”?
Here, you can enter the title, the description shown in the preview window, and then upload the photos and the PDF pattern.
That’s how I do it, and it’s really easy.
I write my patterns in Word beforehand and add the photos there as well. I convert everything to PDF and then into a ZIP file, and then I can upload it.
Upload a single photo as an image file for the cover image, and upload the other photos you want to show in the preview as a ZIP file as well.
Take a look, it’s described here in great detail:
https://www.crazypatterns.net/de/anleitungen-hochladen