Thank you for your ticket and helpful video tutorial.
Currently the "Intro Image" parameter acts as a "quick insert" of images; meaning that you select your desired image and it inserts directly into the article field. At the moment image editing features are reserved for the main article text when using the Ark Editor's image button or the Ark Media editor-xtd button at the base of the article text field.
The original reason for doing this was to provide a fast-insert mode for users who wished to directly insert intro image links, plus it skips the up-until-now unnecessary insert screen that allowed you to set class names, styles & ids etc as these aren't necessary for a simple image link. However since newer versions of the Ark Media add image editing to this additional insert screen there is now a case for not skipping this step. So although this is expected behaviour I have created a Feature Request on our features page for yourself and others to vote & discuss the desirability/feasibility of this request, which would then prompt us to add this to our roadmap of future features. All full list of the Ark Media feature requests can be found here.
You can insert your intro image links as normal and then use the article's editor-xtd button to then crop the image. This isn't ideal but achieves what you currently need.