Here are more details on the scenario.
I want to know how to reference the object I'm editing via Easy Edit in a Java class. I have a list of images in an FS_LIST object. And each image has the code snippet to make it editable in ContentCreator, so as an example we want the editor to be able to change each image:

And when you click edit, the image edit opens, in which I have a custom FS_BUTTON, used to choose an image from an external gallery (if they want to):
<FS_BUTTON
name="st_custom_button"
hidden="no"
icon="fs:new"
onClick="class:class.name.goes.here"
style="firstspirit"
useLanguages="no">
<LANGINFOS>
<LANGINFO lang="*" label="External Gallery"/>
</LANGINFOS>
</FS_BUTTON>

I have Java code written which communicates from the external gallery and the executable class. Basically I can do things like Logging.logInfo("Message here", this.getClass()) when I interact with the external gallery, I can pass and read parameters (using top.WE_API.Common.execute to communicate with the class from JavaScript).
The thing I am missing is how can I get that image entity that I want to edit (in the first screen shot) so I can populate it. Here is a very rudimentary snippet of something I have used in Beanshell to create a section, where you have the context, and from that you can create a Section:
final StoreAgent storeAgent = context.requireSpecialist(StoreAgent.TYPE);
final Store templateStore = storeAgent.getStore(Store.Type.TEMPLATESTORE);
SectionTemplate mainContentTemplate = templateStore.getStoreElement("st_main_content", IDProvider.UidType.TEMPLATESTORE);
Body mainContentArea = page.getBodyByName("main_content");
Section mainContentSection = mainContentArea.createSection("Main Content", mainContentTemplate);
What I need is when the user clicks a button on the external gallery, I call top.WE_API.Common.execute to call my Executable class, I want to update the image section. Similar to that Beanshell example above, at the point I will writing code I only have BaseContext:
public Object execute(Map<String, Object> params, Writer writer, Writer writer1) {
context = (BaseContext) params.get(PARAM_CONTEXT);
return null;
}
So is it possible using a class that implements Executable to get the entity being edited in ContentCreator (first screens shot above)?