Add Image Border Online

What Add Border Does

Add Border works directly on the canvas, not as a filter over your photo. It loads the image into an in-memory HTML canvas sized larger than the original — the canvas width and height both grow by exactly twice the Border Width value, once per side — then strokes a rectangular frame in Border Color around that outer edge before drawing your source image, at full resolution and unaltered, centered inside the new padding. Nothing about the photo's own pixels is touched; the tool adds material around it rather than painting over or resampling it. Solid style draws one continuous stroke at the full Border Width. Double style splits that same width into three roughly equal bands — an outer ring, a gap, and an inner ring — using the same Border Color for both rings, which gives a classic picture-framing look with a thin reveal of empty space between the two lines. Because each of those three segments needs at least a pixel to render, the double effect only reads as two distinct lines once the width is generous enough, roughly 15px or above; at small widths the segments compress and it looks like one thick stroke instead. The border is uniform in a specific sense: one Border Width value applies to all four sides at once, and the corners always stay square, regardless of what shape the photo itself is — this tool does not round corners, and it has no control for a different width per edge or an asymmetric mat. Output keeps the original file's type, so a border added to a JPEG stays a JPEG and one added to a PNG stays a PNG, which matters for the double style's gap: that gap isn't filled with any color, so it renders as transparent on a PNG but as solid black on a JPEG, since JPEG has no alpha channel.