Hello jeroen52,
Thanks for reaching out to the Apple Support Communities! I understand that you take Live Photos on your iPhone and would like to only save the .jpg from these Live Photos to your Windows PC.
One way you can select just the .jpg files is to use the option to "Import > From a USB device" through Photos in Windows. Using this option you can select the items you want to import and where you'd like them to be saved.
Go to the "Import to your PC" section in this article: Transfer photos and videos from your iPhone, iPad, or iPod touch. Select the link to the version of Windows you have on your PC, and follow the steps.
Once you have imported the photos, you can always turn off Live Photos if you would prefer to only shoot a still photo. This would allow you to only have .jpg photos to download. You'll find the steps under, "How to turn off Live Photos," from this article: Take and edit Live Photos.
All the best!