When transparency is useful
Transparent images allow a subject or logo to sit over different backgrounds without carrying an unwanted solid rectangle. PNG is a dependable format for this purpose. WebP can also support transparency, but JPEG does not, so a JPEG export must replace transparent pixels with a color such as white.
Preparing a round avatar
Choose a reasonably large source photo with the subject near the center. A circle crop uses the shorter image dimension to create a square selection, then masks away the corners. If the subject is far from the center, crop the photo first to reposition the focus. Export the circle-cropped result as PNG to retain transparent corners.
Soft corners for interface assets
Rounded corners are useful for product images, thumbnails and mockups. A radius measured in pixels determines how much of each corner is removed. For a visually consistent grid of cards, use the same radius and image ratio across the group. Review how the cut corners look on both dark and light page backgrounds.
Padding and borders
Adding padding creates more breathing room around a picture without necessarily stretching the source content. A border can help an image remain distinct on white backgrounds. These operations are particularly useful for product catalogues, documentation figures, presentations and polished profile layouts.
Export checks
Avoid exporting a transparent edge as JPEG by accident. Inspect the final background, check that the subject has not been cropped too tightly, and keep an editable high-resolution source for future dimensions.