What are some alternatives?
GIMP - GIMP is a multiplatform photo manipulation tool.
Canva - Canva makes design simple for everyone. Create designs for Web or print: blog graphics, presentations, Facebook covers, flyers, posters, invitations and so much more.
Pixelmator - Pixelmator is an image-editing application for Mac and iPad.
Sketch - Professional digital design for Mac.
Affinity Photo - Affinity is the imaging and design suite for creative professionals exclusively for Mac.
Adobe Illustrator - Adobe Illustrator is a vector graphics editor.