Other than the standard WordPress srcset sizes — and those defined in Media Settings — Does GeneratePress (or GenerateBlocks) create any additional image sizes under any circumstances?
I did notice some featured image size options in the customizer which I assume will be sized by GP using CSS only.
(I checked image uploads via FTP and didn’t see any additional sizes. Just wanted to confirm.)
GP doesn’t add any additional sizes, but WP adds more than those listed in the Media Settings.
There is the medium_large size of 768px and theres also sizes over 1024p upto a maximum of 2048px ( if your original image is larger then that ).
Other plugins such as Woocommerce also add there own sizes.