画像にボーダー追加

What this tool does

Add Border to Image wraps your image in a customisable frame. Pick a border style (solid, dashed, dotted, double, inset), tune width, colour, radius, padding, and an optional drop shadow — all rendered live on canvas before you export.

Quick presets

Click any preset to apply curated combos: thin solid, polaroid frame, rounded mat, soft shadow, double border, dashed accent. You can keep tweaking after applying — presets are starting points, not locks.

Position semantics

Inside paints the border on top of the original pixels (image stays the same size). Center splits half inside / half outside (output grows by the border width). Outside leaves the image untouched and adds the border around it.

Privacy

Files stay on your device. For other framing utilities try Matte Generator or Watermark Maker.

What does Add Border to Image do?

It surrounds your image with a customisable border or frame, with optional padding, rounded corners, and a soft drop shadow. Everything renders on a canvas in your browser.

Who needs an image border?

Photographers framing portfolio shots, social media managers prepping consistent posts, e-commerce teams building product cards, and anyone preparing print-ready proofs.

When should I pick Inside vs Center vs Outside?

Inside paints the border on top of the image so the output stays the original size. Center splits the border evenly along the original edge. Outside extends beyond the image, growing the canvas — best when you want clean polaroid frames.

Where is the file processed?

Entirely in your browser. The image is decoded with createImageBitmap and the final canvas is exported via canvas.toBlob.

Why does the file size vary by format?

JPG re-encodes with lossy compression, PNG keeps every pixel and supports transparency, WebP balances both. Pick PNG if your border has transparent areas (e.g. radius corners with no background).

How do shadows interact with transparent backgrounds?

Shadows are painted onto the canvas before the border, so a transparent background still produces visible shadow halos around the framed image.