How to Add a Before/After Image Slider in Shopify Testament Theme

The before/after slider is a native Testament block — shoppers drag a handle across two overlaid images to compare them, useful for skincare, renovation, fitness, and similar results-driven products.

Steps

1. In your Shopify admin, go to Online Store > Themes and click Customize on Testament.
2. Open the page you want it on and click Add section.
3. Choose Before / After image slider.
4. Upload your "before" image and "after" image — same framing and angle makes the comparison read clearly.
5. Set the starting slider position and any labels ("Before" / "After").
6. Click Save.

This only works well when both images are shot consistently — mismatched angles, lighting, or cropping make the comparison confusing instead of convincing.