A collage layout should not crop faces, text, or key subjects without the user's awareness. Add photos with different aspect ratios, choose a layout, and inspect each crop before exporting. Then compare spacing, borders, background, color, and output dimensions with the preview.
Test rearranging photos and returning to a previous layout; the order should remain predictable. For a report, use non-sensitive sample images and include layout, source dimensions, crop positions, export size, and the photo that changed unexpectedly.
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