You can’t copy images from google slides to anything. Try doing this right click image on google slides and save to google keep. (If the save to keep option doesn’t show up, add the app to slides.) From keep, you can right click the image and copy → paste to figma.

You could copy images from Google Slides to Jamboard. Figma should enable this feature.

What I found better is to go to the slide and then File → Download → Scalable Vector Graphis (.svg, current slide). You can then export that .svg slide to your Figma

Yes going to slide and then File → Download → Scalable Vector Graphics (.svg, current slide) works, however its very time consuming as it only download per slides contents and in my case all the editable copies automatically pathed causing more work to edit.