Include descriptions for action form buttons explaining e.g. the difference between Scale and Resize...

Scale and Resize are used interchangeably in English often enough that this is going to be confusing. It's hard enough for people to understand the difference, much less remember which is which. A simple field description would really help here.

We could use walkah's descriptions for Core image handling: drupal.org/node/16358

Scale

resizes a given image to fit within a given width / height dimensions, while maintaining aspect ratio (not distorting the image). - this function can be used to generate thumbnails, or ensure a maximum resolution, etc.

Resize

similar to scale (but will not respect aspect ratio - may well distort the image).

Crop

crops an image to a given rectangle (defined as top-left x/y coordinates plus a width & height of the rectangle).

Crop is pretty self explanatory although it is unclear what kind of values are accepted, pixel coordinates? percentage coordinates? keywords like 'center'? Which raises an important question, is it possible to crop from the center of the image when you have no idea what the x-y coordinates are going to be?