filter field by type (making extension)

I need to filter the fields of image type in my extension, how to proceed?
I read the documentation and found nothing about it.

// filter field defined as image

You should refer to the existing built-in extension, such as “DateTimePicker” or “TimePicker”, see the code in “field_edit_text.ejs” file for your reference.

my question was perhaps not well thought out.
I want to filter the image type fields in the extension definition window.
Like the case of datetimepicker. it filters only the fields defined as date in its extension configuration window.

something related to the type of the extension, because when I change the type of my extension to Date / timer picker,
the fields are filtered for the date type.

If you setup your field to display “IMAGE” from “View Tag” pane under “Fields” setup, then you may check by using “FldViewTag” is equal to “IMAGE” in your extension side.