That would be a question for the Sony software people.

they tell me it's a problem with email program!

Most of those programs use the system default email client. I have never heard of the Sony software but I know it has nothing to do with Thunderbird.

This will work only if the Sony program supports SimpleMAPI calls to the default email program. On W10, Winkey+R and type control panel to open Control Panel, and go to the 'Set Default Programs' window, select Thunderbird, then 'Choose defaults for this program', then check all the boxes as indicated in the picture,

Sending from Playmemories may still not work, but perhaps it will.

I followed your directions but playmemories still won't open default email program to enable me to email images. I am so frustrated about how to get images from camera to email. I may just have to rely on phone camera. This is not why I bought a camera. thanks for trying to help me.

It should be possible to import photos from a digital camera or smartphone to your computer, and then send them as attachments in TB. It doesn't even require any special software: plug the camera into a USB port on the computer and it will ask you what to do. Or, open the Photos app that is part of W10 and click Import in the upper right corner.

If your PC has a card reader, insert the camera's memory card and browse the contents with File Explorer.