RoundedPic

This app applies rounded corners, masks, overlays and borders to images. You can adjust the corner radius from 0 (no rounding) to half the width of the smallest side of the image, enabling you to create anything from subtly rounded edges to perfect circles. Add borders with color.

The app features masking and overlay capabilities. For example by applying a mask with a transparent region in the shape of a star, the app can crop your image to a star-shape, leaving the rest of the image transparent or filled with a customizable solid background color.

The app supports multiple sources for images. You can choose images directly from the Photos library, browse local files, or select files stored in iCloud Drive. For convenience, the app includes a collection of built-in masks to help get started quickly.

Making masks is simple using the Preview app. Simply select the whole image, then cut leaving a fully transparent image. Now add shapes, lines with the markup editor. Save the image to file format that supports transparency - such as PNG or HEIC. Then load the mask from either the file system or Photos.