Don't want alt text to show in pop up

[letsgofishing]

I've attached alt tags to all my images so that Google's happy, but to write different ones for each image (around 150) is a PITA so a large number of them are copy and paste.
But I DON'T want them to show in the image pop ups - is there a way to prevent this?
Screen captures attached.
May thanks,
LGF