In Image Hopper Editor 2.1 you can enable a frame feature to allow users to add a unique border to the images.
// Add frame utility to editor.
gform.addFilter('image_hopper_filepond_config', function(config, FilePond, $form, currentPage, formId, fieldId, entryId, files, inputField) {
config.imageEditor.editorOptions.utils.push('frame')
return config
}, 20 )