Yes, with the extensions Blacklist config it is possible to exclude certain images on your site from WebP conversion. You can add any string or RegEx as comma separated list. Any -tag matching with any of the given strings/RegEx will be excluded from conversion.
Example 1: Exclude Logo named logo.png:
logo\\.jpg
Example 2: Exclude Logo named logo.png AND all images through WYSIWYG editor:
logo\\.jpg,wysiwyg
Example 3: Exclude images with a certain css class, e. g. product-image-photo:
product-image-photo
Note: img-tags with data-nowebp="true" are excluded from conversion by default.