A border adds to the photo, not over it
Some editing tools "add a border" by painting a coloured strip on top of the outer edge of your existing photo, which quietly crops away whatever was there. This tool works differently: it opens a larger canvas, fills it with your chosen colour, and places the original photo on top, untouched. A 30px border on a 1200×800 photo produces a 1260×860 result — every original pixel is still there.
Picking a width that looks deliberate
Border width works best scaled to the image rather than fixed at one number. Somewhere around 2 to 4 percent of the shorter side reads as an intentional frame — for a 1200px-wide photo, that's roughly 25 to 50px. Go much thinner than that and it can look like a rendering accident rather than a choice; go much thicker and the frame starts competing with the photo for attention instead of supporting it.
Colour: the classic choices, and when to break them
White is the default here for a reason — it mimics the mat board a physical print sits behind, and it works with almost any photo regardless of its own colours. Black reads more formal, closer to a gallery frame. Beyond those two safe defaults, pulling the border colour from something already in the photo — a wall, a sky, a piece of clothing — usually looks more considered than an unrelated colour picked at random.
Rounded corners: a different look entirely
Checking "round the corners" clips the entire result — border and photo together — to a rounded-rectangle shape, with the area outside it left transparent. This is the same treatment used for app icons and card-style posts on social platforms, and it changes the feel from "framed print" to "UI element." Because the corners need real transparency to look right, rounded output is always written as PNG, even if JPG was selected before you checked the box.
A whole folder at once
Drop in as many photos as you like and the same border width, colour and corner setting applies to every one independently, with a single ZIP download once they're all done. There's no file count limit, since nothing is uploaded to a server that would need to handle the load.
Nothing is uploaded
The whole process — opening the larger canvas, filling it, placing the photo, clipping the corners if you asked for that — happens entirely inside your browser. The photo never leaves your device, and there's no size limit beyond what your own hardware can hold in memory.