Imagefield_crop field in custom form? How can I add through the form API an image upload field with the cropping functionality implemented by this module?

http://drupal.org/project/imagefield_crop/

I'm using Drupal 7. I need to implement an image upload field with cropping functionality. If there's another module that does the same job as Image Crop and plays more nicely with the form API, that's fine.
I ended up getting this working by using a module called Form Block and just putting the block containing the node form in the content. For some reason I never figured out, just calling drupal_get_form on that node form just did not work, even with the right node module files included. So, hopefully someone else struggling with this will be able to learn from this question