An example for using Gravity Perks Populate Anything with Image Choices where the image source is a form entry, and another Image Choices field

gppa_image_choices_from_form_entry_example.php

<?php
function gppa_image_choices_from_form_entry( $choice, $field, $object, $objects ) {
	$object_type = rgobj($field, 'gppa-choices-object-type');

	if ( $object_type != "gf_entry" || !function_exists('gf_image_choices') || !gf_image_choices()->field_has_image_choices_enabled($field) ) {
		return $choice;
	}

	$templates = rgobj($field, 'gppa-choices-templates');
	$template = (!empty($templates)) ? rgar($templates, 'imageChoices_image') : "";
	
	if ( empty($template) || strpos($template, 'gf_field_') === FALSE ) {
		return $choice;
	}

	$source_field_id = str_replace('gf_field_', '', $template);
	$source_form_id = rgobj($object, 'form_id');
	$source_value = rgobj($object, $source_field_id);
	
	if ( empty($source_form_id) || !GFAPI::form_id_exists( $source_form_id ) ) {
		return $choice;
	}
	
	$source_field = GFFormsModel::get_field($source_form_id, $source_field_id);

	if ( empty($source_field) || !gf_image_choices()->field_has_image_choices_enabled($source_field) ) {
		return $choice;
	}
	
	foreach( $source_field['choices'] as $source_choice ) {
		if ( rgar($source_choice, 'value') == $source_value ) {
			$choice['imageChoices_image'] = rgar($source_choice, 'imageChoices_image');
			$choice['imageChoices_imageID'] = rgar($source_choice, 'imageChoices_imageID');
			$choice['imageChoices_largeImage'] = rgar($source_choice, 'imageChoices_largeImage');
			break;
		}
	}
	
	return $choice;
}
//add_filter( 'gppa_input_choice', 'gppa_image_choices_from_form_entry', 10, 4);// all forms
//add_filter( 'gppa_input_choice_FORMID', 'gppa_image_choices_from_form_entry', 10, 4);// specific form (ID)
//add_filter( 'gppa_input_choice_FORMID_FIELDID', 'gppa_image_choices_from_form_entry', 10, 4);// specific form and field (ID)