Choose 720 × 1280 for vertical 9:16, 1280 × 720 for horizontal 16:9, or 640 × 640 for square 1:1 in the current preset set. These are documented minimum image dimensions, not permanent platform guarantees.
Choose the placement first
Vertical creative occupies the most phone-screen space. Horizontal works when the source cannot be reframed vertically, and square is a flexible compromise. Open Image Resizer, select the matching preset and confirm that the displayed target dimensions are correct.
Protect the visual subject
Use Fill for edge-to-edge creative, then check whether the center crop removes a face, product or text. Use Fit when every part must remain visible; choose a deliberate background color so the added area feels designed rather than accidental.
Avoid unnecessary quality loss
Start from the original file, not an image already downloaded from social media. Export once at the target size. JPG at high quality is practical for photos; PNG is better for crisp graphic elements but usually produces a larger file.
Treat presets as maintained references
Platform requirements change. CollagePlus shows the source and review date beside its presets instead of presenting them as permanent rules. Recheck official specifications for paid campaigns or a placement with strict validation.