Canvas and frame
Border thickness and inner spacing do different jobs
Border thickness defines the visible outer frame, while inner spacing gives the photograph breathing room inside that frame. Increasing either can enlarge the composition or reduce the image's share of a fixed aspect canvas. Watch the output dimensions and image zoom so a generous matte does not make the subject unexpectedly small.
Style
Choose color and depth from the image, not from the preset name
A white studio border suits clean listings and feeds; darker mattes can contain bright artwork; gradient glow, glass, or shadow treatments suit selective promotional graphics. Sample a supporting color rather than the most dominant one, and keep decorative depth subtle around text, products, or documentary images where clarity matters more than effect.
Destination
Use aspect presets to add space instead of cropping the subject
Square, portrait, story, and landscape canvases can adapt a photograph to a placement while preserving the full image. Extra bottom space can create a Polaroid or caption area. Check safe areas in the target app, because interface controls may cover edges even when the file itself has the correct ratio.