I have chosen the option Migrate images from products descriptions and categories descriptions
"I have chosen the option Migrate images from products descriptions and categories descriptions. Why can’t I choose the additional option Strip HTML from categories and products names and description?"
The images in product descriptions are mainly realized in HTML and if you select this option, the images will be striped from descriptions. The option Strip HTML should be selected in case the HTML code is configured incorrectly or HTML formatting at the Target store is not necessary.
If you want the images in descriptions to be migrated to your Target store you should choose the option Migrate images in products and categories descriptions. These two options are contradictory and can not be chosen simultaneously.