Since you are doing this manually, then I think your best bet would be to import them separately with different settings (you could create a second account with different import settings and even log into a second LF instance on the same machine if you wanted), or just do it on a more powerful machine because OCR is especially resource-intensive.

The problem is that the OCR step applies to the generated pages not the original source file, so by that point there there is no more "jpeg" or "pdf" to exclude. You can tell LF not to generate pages for jpeg, but that's not really what you want either.

If you use Import Agent, then you can create a filter on the import agent profile to only target specific file types; you could configure one profile for your PDF files, and another for your JPEG files with the OCR option disabled.