Is it possible to auto-generate PDF preview images with Craft 3 transforms?
Or are there any Craft 3 plugins that do this? I see a few Craft 2 versions.
Craft 3 doesn't do this natively and I'm not seeing any existing Craft 3 plugins that would do this, so at the moment, you'd need to write your own.
I created a plugin specifically to do this - https://github.com/bymayo/craft-pdf-transform
It takes Asset PDF files and coverts them to JPEG / PNG files automatically when they are uploaded.
Or, do theres a Twig method that lets you convert the PDF to an image if the image already exists in Assets. But this can be a bit labour intensive on the server to do when a template is rendering so is only advised for small files.