Know the pixels you actually need.

Divide pixel dimensions by your chosen PPI to estimate physical size; calculate again after cropping.

A resolution label alone does not create image detail; inspect pixel dimensions and the intended physical size.

Calculate from the pixels that remain after the final crop, not from the original camera file.

Choose crop, border or a different format explicitly; do not stretch the picture to hide a ratio mismatch.

Viewing distance and print process matter;300 PPI is a common planning example, not a universal approval rule.

Recover the camera, scan or artwork master before enlarging a compressed derivative.

A screenshot is usually a last-resort source; recover the underlying image or document first.

Capture a clean, adequate scan where possible; enhancement should not replace avoidable source-capture work.

Calculate the actual required output and evaluate a physical-scale detail proof before ordering large prints.

Skip enlargement when the source already meets the job—or when generated detail would undermine the purpose.