Squarespace Print-Size Selector Integration

I’m ready to extend my Squarespace photo-print store so each image shows only the sizes I choose for it. On the back end I need a simple panel—checkboxes are fine—where I can tick whether a photo is offered as a square, a standard 5:4, or one of my wide, narrow landscape formats... (Budget: $250 - $750 USD, Jobs: CSS, Frontend Development, HTML, JavaScript, Squarespace, Web Design, Web Development, Website Design)